The problem is that illustrations are generally much more use than pictures, with the possible exception of hominid skulls. Most fossils look like chunks of rock; you need to be pretty well trained to know what you’re looking at, whereas an illustration will show you the key stuff straight away -- the illustrator (hopefully) has left out the extraneous stuff that’s just a distraction to the inexpert eye.
Here, for instance, is quite a
clear fossil...
...see what I mean? Let alone realising the significance of something like this:
So I’d say stick to hominids. Most non-human-ish fossils are too alien for us to make sense of them in an at-a-glance, compare-one-to-another way. There are plenty of books with good pics: Tattersall & Schwartz’s
Extinct Humans springs to mind.
But if you
do want non-hominids, you might try the
Palaeos site (tons of good stuff there), and the
Devonian Times has lots of pics as well as illustrations.
Cheers, DT