For posts here, just about anything will do. Everything on the market will take pictures with more color depth and/or size, than this site will support.
That said, I would choose one of the Canon products. They make the small form factor you're after, AND, Canon bundles some nice software for tweaking the images to fit on this board.
EDIT: Canon also uses CF-cards (CF=CompactFlash=good) for memory (digital film)
If you think back to the VHS vs Beta wars; CF is like VHS . . it seems to emerging as the standard. Sony, again, has their propriatary versions, as do others.
The deal on the very small (if not the smallest) Canon Elph is
HERE @ ~$225