That sounds like a great idea. The real question for me is if we are going to do another mosaic, what will be the "big" image. I think I was pretty lucky to happen upon the idea for the first post mosaic, but I don't want to simply copy the old format. Maybe a variation on the original would be good?
Sure, a different format perhaps. I do like the BIG image as the spider is the main purpose and should get center-stage!! Something similar to the first, just changed some...perhaps a black spider vs. a white one?? Sumpin' like that!!
I downloaded your Caedes image and played around with it a bit... I kinda like it processed in PS or Elements (Filter-Texture-Craquelure). I don't know how that would go in the background here but another idea would be to use the original in that process and then lighten it as is the current mosaic. Just giving food for thought so if you like some other process... by all means! :o)
Edit: That said, I do like your Caedes as it is... I especially like the unobtrusiveness of your current design.