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Discussion Board -> Desktop Wallpaper, Art, etc. -> Image Quality

Image Quality

PrettyFae
05/28/05 8:06 PM GMT
Ok, I've said stuff about this before, but I just want to see if anyone could help me out...
Alot of my images are over 500KB, so when I upload, the quality always looks reallly poor and the image becomes blurred...Is there anyway of compressing images so they use less space, but still have identical quality as before?
Help would be greatly appreciated here! ^_^
Thanks
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PrettyFae x...Spread the Passion...

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kjh000
05/28/05 9:16 PM GMT
I've been pondering this, or a very similar question, the last couple of days. I've seen one thread once on a similar issue but I didn't get the final point I think... At the time I didn't think my images were that affected in the re-compression that I gather takes place once you submit an image here.

I thought that if I made my image small enough it would be left alone and not tampered with. My last couple of submissions have lost considerably in details. First I didn't see it but just took them down and thought I must have been a bit tired when finishing the image since it looked so crappy now. My last piece "Shadow Wars" I finally saved from caedes to my HD and compared to the file I had uploaded... It looked like a gaussian blur had been applied and much of the details were gone. (Not that it is such an exceptional piece to begin with but anyway... ^_^ (I did put some work into it...))

My question is how big a file can I upload here? I was under the impression that it was better to submit reasonable small files (largest possible size naturally, that is properly explained in FAQ, but not this issue). (And is it only jpg format you accept?)

And... perhaps I wonder if there are some funky settings on the compression here that makes images dominated by some colors, say red, are more compressed then others? I noticed PrettyFae had problems with the same shades of red that I had in her "Red Rose". Is that pure chance?
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PrettyFae
05/28/05 9:27 PM GMT
Yeah, I think it must be something to do with that red because if you compare my Red Rose image to my Frozen image (which are both relatively the same size) you'll notice that the icy blue is far more sharp than the deep red...
But anyway, thanks for replying, Klas...
In answer to your question about the file size, when I asked +tbob, they said it was best to upload images under 500KB...but that's all I can say really...sorry.
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PrettyFae x...Spread the Passion...
kjh000
05/28/05 9:30 PM GMT
I was thinking about exactly that image as a comparison too. I just wasn't sure if they had the same approximate file size.

[Edit, I wrote this comment during PrettyFae posted her comment above so I added my first part of this post after that.]

Or to put it this way: What is the goal with the on site compression of our submissions? If it's to get a specified (maximum) file size, why would you re-compress images if they meet this standard. (Since I don't know it exactly I've been aiming at 512k or (most oftenly) less. Maybe it's too large still?) I understand there are some technical issues about making the different sizes for downloading here and such. I just wish to hear clearer guidelines.
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DixieNormus
05/29/05 1:14 AM GMT
You can compress these images with Photoshop, or an almost as good (unbelievable, I know) program called Gimp 2.2, and you can resize your images for wallpaper resolutions. I do it all the time, and haven't had any problems with pixel loss or color change.
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( /-\ |= |) |= $
d_spin_9
05/29/05 4:08 AM GMT
i think with your pictures it has alot to do with not the colours, but the brightness of the colours. naturally you will see more in the image that is brighter, and without realizing it you probably lost a fair bit of detail in the processing between the two images. i think why the 2nd looks less detailed is because i bet you darkened it some way where it just clipped all the detail off the dark end, leaving it pitch black
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The heavens declare the glory of God, the skies proclaim the work of His hands.
kjh000
05/29/05 6:00 AM GMT
Thanks for the input.

I have no problems compressing or resizing images... But thanks anyway. :)

And it's absolutely no change on my behalf in that image, it's the exact same file that I submitted here and the image that I downloaded from here as a result from that submission that I compared. It's no difference in brightness between them. But I guess you can have a point with the brightness being an issue since the image is quite dark...

My question is what happened here on caedes when I uploaded the image. I know there is a feature with automated compression of the images, what I don't know is if I can dodge it if I make my file sufficiently small (something I've been trying to do) or if I can avoid getting blurred images by submitting (quite) larger files.
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PrettyFae
05/29/05 9:07 AM GMT
Hmmm...I reuploaded one of my images which was under 500KB but it's still really blurred :(
I don't get what happens here either, Klas...the images always seem perfect on my HD...
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PrettyFae x...Spread the Passion...
kjh000
05/29/05 9:49 AM GMT
I'm quite sure they are too. What we need to know is how we should or should not compress our images to make them look as good as possible here. Only the big boys can answer us properly I believe. I've heard of people uploading files that are several MB in size. I just thought it would be nice to have a proper directive to sort out if that is ok before I start doing that.

Please, anyone, point me in the direction of an answer to my questions if there are already any out there. I did search the forums for an answer but I came up short of any definite such. (Maybe it could have been resolved if the search wasn't limited to the top 100 or so hits (I've not counted but it seems to be like that at least)... ^_^ Hint,hint...)
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::Benroy
05/29/05 11:15 PM GMT
I'm surprised Fae that all your images aren't over 1MB because you upload at 1600 *1200 like I do. Most of mine are usually between 1 and 2.5MB in jpeg format.
What I usually do when I finish an image is save it as a BMP version for my hard drive as this has no compression and therefore no loss in quality. I also save as a jpeg version to upload here. When saving as a jpeg version in photoshop I always go for maximum quality in the options menu that comes up, I think is number 12. By doing this the compression is kept to a minimum and therefore quality kept as high as possible. I had the same problem when I started here and asked the exact same question. I'll try and find the discussion for you as it's better explained there.

Cheers..........
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::Benroy
05/29/05 11:36 PM GMT
Here's the discussion I had many moons ago.......

http://www.caedes.net/Zephir.cgi?lib=Board::Topic&id=200871
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kjh000
05/30/05 7:23 AM GMT
Thanks for the input Ben, and the heads up on that discussion. It's close but not exactly what I was thinking about (maybe Fae got her answers). But it sure touches upon the same subject. If I saved all my work in maximum quality I'd sure have files larger then one or two MB to upload here, I too upload at 1600x1200 in image size. I just can't find info on what is considered acceptable for the submissions.
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PrettyFae
05/30/05 9:43 AM GMT
Thanks Ben...you know...I do the exact same thing as you when saving in PS...I always save at maximum quality, number 12...but surprisingly, most of mine are under 1MB...

I really do think though, that the images me and Klas have been talking about became blurred because of their shade of red...I know that sounds silly, but it has to be true!
Especially as the only two blurry images I have are done in that colour, and so is Klas'...and both of mine are only about 350KB as well...also, I have actually uplaoded quite a few that are over 1MB that are not red, and *they* have come out fine...any ideas why this might be, anyone?
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PrettyFae x...Spread the Passion...
::CaptainHero
05/30/05 9:55 PM GMT
Hell, I didn't realise 500kb was the recommended limit. It's only when my images get up towards the 1mb size that I begin to worry and recompress them...

With regard to the question, it is maybe something to do with the resizing code that the site uses (presumably through perl).
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"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." Bertrand Russell
kjh000
05/31/05 7:04 AM GMT
I'm not sure that is the case (anymore, if it ever were). That's part of what I'm trying to elude here...
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+mayne
05/31/05 3:24 PM GMT
Everytime you save a jpg file you will loose quality. So the when it gets to Caedes it has been saved at least three times.
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Darryl
PrettyFae
05/31/05 3:27 PM GMT
Well that would explain some of it...but what has Caedes got against deep shades of red?
Why is that particular colour always the most blurred?
Thanks for the responses, though, everyone ^_^
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PrettyFae x...Spread the Passion...
kjh000
05/31/05 3:42 PM GMT
Hehe... lol! Exactly...

I know that Darryl. But thanks for the input anyway. It does like Fae say not explain the difference in different images of approximate the same size at upload. Is there some place I can read about the on-site compression that takes place and what settings it uses. (I guess I might not understand it if it's too technical... but anyway.)

And... I'm curious of the official opinion on what kind of files to submit (and eventual limits in size one ought to consider). It doesn't say in FAQ and I think it should if there is a preference and certainly too if there is no such things to consider.
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+mayne
05/31/05 3:42 PM GMT
Another thing to consider is the program you use to view the image. Are you using your browser to view the image from Caedes and comparing it to the same image in windows picture and fax viewer? The latter of which is garbage for viewing images.
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Darryl
+mayne
05/31/05 3:44 PM GMT
I recall there used to be a 500KB limit...that doesn't apply anymore;-)
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Darryl
PrettyFae
05/31/05 3:44 PM GMT
I was comparing the image from Caedes to the one on my desktop ;]
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PrettyFae x...Spread the Passion...
kjh000
05/31/05 3:47 PM GMT
I'm comparing in the same program: GraphicConverter for mac and to my knowledge there should be no issues with that. It's not crappier then most imageviewers I'd say. (On the contrary I'm quite happy with it.) The image in question does however look just as crappy all in all as it does here as viewed in the browser. ^_^ I'll send you the copies if you have doubts of my judgement. (No offence taken in that case and none what so ever meant.)
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kjh000
05/31/05 3:52 PM GMT
I've gathered the limit doesn't apply anymore... I'm just wondering what the limit or recommendation is atm. I like to abide to the rules that are set or at least know if there is no rule to follow. I guess I could start uploading 20 MB illustrator files just for the fun of exploring the issue but I'm not really feeling like learning by trial and error here. I'm not in the mood atm at least... ;)
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=xentrik
05/31/05 3:59 PM GMT
From what I understand, the software archives the original submission (which can feasibly be 1-2MB at 1600x1200). The gallery software then makes a more compressed 1600x1200 copy, along with copies at all the other resolutions. I believe this is a bandwidth-saving measure more than anything, because 9 times of out 10 (or more) there is very little quality loss for an image at one half to one quarter the size.

My guess is that the jpg algorithm just isn't that good at dealing with images of similar color. Take a look at this page, it shows some tests (specifically with contrasting reds/darks) and contains this quote: "...it is important to remember that JPG is designed for photographic images. Computer generated images with sharp transitions between areas of uniform color are particularly difficult for JPG to handle. ... Also, colored stripes that are only one pixel wide, as in the above image, cause problems for the great majority of graphics programs that force subsampling of chroma information in 2x2 blocks".
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+mayne
05/31/05 4:01 PM GMT
There is definately some loss in quality not only in the reds but all colors visible to my eyes. It appears as a loss in tonality which is impossible to escape in JPEG compression. There is no where we can read about the compression that takes place...unless we have a mind reader on site;-)
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Darryl
kjh000
05/31/05 4:15 PM GMT
Great info Mike. :) Thanks! I'm still concerned about the possibility to submit different types of files though.

I'll check that page out when I get more time on my hands. I'm a terrible mind reader btw... That might explain why I ask so many silly questions... (lol!)
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+mayne
05/31/05 4:25 PM GMT
Here is another source of info about jpeg images.
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Darryl
+mayne
05/31/05 4:57 PM GMT
Here is a possible answer to the red phenomenon.
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Darryl
kjh000
05/31/05 5:43 PM GMT
Thank you Darryl, I'm glad for the additional info. I'm aware of the general idea of the compression in formats like mp3 and jpg. It's always nice to know more details though. I'll check it out more thoroughly later.
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::nmsmith
06/01/05 12:44 AM GMT
I had the same problems until I started doing this in Photoshop - 1) File - Save for Web. 2) Make sure the settings are JPEG - OPTIMIZED is checked - Quality = Maximum with the slider clear over to 100. Make sure all other check boxes are unchecked and that there's no matte and no blur set. That should make you happy. :)
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*caedes
06/01/05 3:16 AM GMT
When you are working on an image, you should never save it as JPG. Use a lossless format like PNG instead. Otherwise you will be repeatedly recompressing the image with each save and losing infomation each time. Only use JPG for the final copy that you plan to distribute yourself. Uploading the image to caedes.net counts as an editing step, so you should try to use a lossless format here too.

The reason that the web site compresses the image (using ImageMagick JPG quality=90) is in orer to maintain a uniform level of compression for all the images on the site. Otherwise we would be wasting bandwidth when someone uploaded a photo that is not compresses optimally (as zentrik has said).
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-caedes
prismmagic
06/01/05 5:30 AM GMT
Absolutly Right saving to aJPG. every time decresses the resolution of an image. I personaly either use the programs file format or save as a tiff that way I loose o quality or sharpness.
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kjh000
06/01/05 6:00 AM GMT
I would never dream of saving as JPG during my editing process. I've gathered as much way before even joining caedes.net.

I use PSD as a baseline format in my processing chain. I was just assuming that my submission was my final copy and not a step in the editing... Silly me. ^_^ (That's why I think this needs to be in the FAQ.)

I'll still consider like Nathan said to simply submit a maximum quality JPG-file. I'm glad for the extra info. Now I only need to try and submit a PSD file and see if that does the trick. ;) I'm glad I'm not surfing with a slow modem... ^_^
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PrettyFae
06/01/05 9:41 AM GMT
So...are you all saying that you don't have to upload your images in the JPEG format?
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PrettyFae x...Spread the Passion...
kjh000
06/01/05 10:07 AM GMT
Seems like it but I'm still not sure what formats are accepted. I've asked so many times now that it seems almost rude to ask again.
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PrettyFae
06/01/05 10:20 AM GMT
Hehe...ok...I'll ask for you ^_^
Is JPEG the only format accepted on Caedes?
If not, which other formats can we upload our images in?
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PrettyFae x...Spread the Passion...
+Piner
06/01/05 10:36 AM GMT
JPEG is the only format accepted, for now, I believe.I think caedes would like to add the superior format "PNG" (Portable Network Graphics). That image format was originally designed to replace GIFs. Although it has been an official Internet image type since 1996, its adoption on the Web has been surprisingly slow. It can handle truecolor graphics (millions of different colors). PNG compression is lossless, which means that unlike JPEGs, there is no degradation of image quality. PNG is an Open Source image format, so you can use it however you want. All major browsers can currently view PNGs.
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The work of art may have a moral effect, but to demand moral purpose from an artist is to make him ruin his work. (Johann Wolfgang von Goethe - 1832)
kjh000
06/01/05 10:37 AM GMT
^_^ lol! Thanks!

Since the first question is sort of answered, I'm eagerly awaiting some clarification on that second part.
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kjh000
06/01/05 10:40 AM GMT
Ok, I missed your post there Tom... Sorry.

But now I'm even more confused. ATM I'll stick to JPG with minimum compression then.
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*caedes
06/01/05 10:47 AM GMT
I've personally verified that the software will work by uploading either jpg, tif, or png format images. When I coded the upload script I did not put a specific requirement on the format. As long as the underlying image manipulation library (ImageMagick) recognizes the format it will be fine.
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-caedes
PrettyFae
06/01/05 11:09 AM GMT
Ok, thanks for all the replies ^_^
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PrettyFae x...Spread the Passion...
Aeires
06/01/05 1:12 PM GMT
One of the most precise and versatile programs is Irfanview, www.irfanview.com . It's a free photo editor that can handle about every file format out there. When you save to jpeg using this, it allows you to select a percentage between 1 to 100 for the compression level. Because of this it's more precise and can tune in files to less than 500kb more accurately than photoshop.
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"I create art to find people who think like me." Man Ray
kjh000
06/01/05 2:30 PM GMT
Thanks for that caedes.

I don't think Irfanview works on mac but the program I use to save to JPG have that same option with the compression as you described (plus the rest you said ^_^). That's why I dont use PS for that too. Doesn't matter as much though once you decide to save with 100% quality.
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::vamoura
06/01/05 3:52 PM GMT
Well I'm learning things here, Thx guys for bringning this up!:0))!
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PrettyFae
06/01/05 3:53 PM GMT
No probs ^_^
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PrettyFae x...Spread the Passion...
::CaptainHero
06/01/05 9:41 PM GMT
I always thought we had to upload as a jpeg. Now I find that's not the case, I will have to think about uploading as PNG or maybe even TIF.
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"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." Bertrand Russell
+Samatar
06/02/05 2:04 AM GMT
Yeah, so did I. Good to know...
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-Everyone is entitled to my opinion- Visit the new improved rescope.com.au
=xentrik
06/02/05 2:47 AM GMT
Well, these are your choices. Since the PSD format is included, you could presumably upload stuff direct from photoshop. Realize, however, that the site is still going to recompress the image for the galleries, so this isn't going to solve the root cause of this discussion. Not trying to rain on any parades, just pointing out...
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kjh000
06/02/05 5:42 AM GMT
Yea, I found that page too Mike... So over 90 formats is possible to upload... ^_^ I'm not sure it's still a problem like you say though. My personal copy of compressed jpg, the size of about 500k still got enough details to be ok by me. I'm quite sure I'll be happy with the onsite compression as long as I don't push the limit at home before submitting the piece and upload an uncompressed one.
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kjh000
06/05/05 11:16 AM GMT
I didn't believe you Mike, but I basically stand corrected. I tried to submit the full 5,5MB PSD file of my "Under the Surface" and it turned out only marginally better and a wee bit bigger. The first file was 336,8k after your re-compression of my submitted 465,2k JPG and the last upload turned out as a 351,6k file.

With my software (I use GraphicConverter for this) I have to compress it down to 88% quality to make it as small as 360k, 90% compression would make it 408,6k in my case and none of those files are this blurred. Are you going to tell me it's only because I use a mac and they have such great software that my images can retain an acceptable amount of details during my compression?
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Romane
07/10/05 11:06 AM GMT
Good morning
I'm already stuck with the .jpg format - that is all my camera saves it at, and then a little compressed (damn). Before I do any work on an image, I resave it using either IrfinView or Gimp 2.2 at nil compression, which usually then blows it out from an average of 800Kb to 2.5 to 3 Mb. Ok, so I start the entire process with some image loss - no choices so I have to live with it and make the best of it. The only time then I apply any compression to the image is when I make a copy, resize the copy to 1600x1200 and at around 90 percent of original, which brings it back to an average of 600 to 8000Kb, and it is this copy that is uploaded - the originals are retained at nil compression. I haven't seen any noticeable degredation between the uploaded image and the image subsequently available for downloading. I reapply some compression as it takes an awefully long time to upload a big file on only a 56K modem connection :)
Enjoy your day
Romane
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Success is found by having the courage to let go of known shores.
PrettyFae
07/10/05 11:09 AM GMT
Oooh...I shall have to try that, Romane :]
Thanks for the feedback.
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Romane
07/10/05 11:28 AM GMT
Good morning
<bows> hope it helps resolve the problems. There is some very interesting discussion above between your initial post and here. Thanks for asking the question, I have as a result learned some more.
Enjoy your day
Romane
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Success is found by having the courage to let go of known shores.
::Flmngseabass
12/23/17 7:36 PM GMT
Here's a weird issue. Today when I tried to upload an image to the site as soon as I click on the "upload" button my chrome browser closes. I tried in with MS Edge and get the same thing. Any idea's out there???:):)
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BB
+mimi
12/24/17 4:59 AM GMT
I find MS Edge to be weird at times. I usually just shut down & restart

I know I am not much help here!

Merry Christmas.
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~mimi~

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