The issue that I've found with the IMVU catalog is that sometimes you can't view the full image, so you have to try and guess based on a 100x100 icon. Maybe the image would show up underneath the description if I enabled IMVU on NoScript but I just don't feel it's worth the risk of doing so.
Images like this:
http://i.imgur.com/UxA4bYt.png
Were found by going onto e621 and searching "lesbian giraffe" and going through the numerous pages until I found the correct one. On pages where there were no direct links to the original image, I had to go and find the artist on FA and go through their gallery.
http://i.imgur.com/hGDlMSC.png
"ringtail cat + female + nude"
http://i.imgur.com/eAueduA.png
"bluejay + female"
I can't imagine there's an easier way to do this, which is why we need more people actively working on it. It's a lot of work, yes, but I don't think there's any other way to do it -- image comparison programs probably wouldn't be able to pick up an image that small.
Well, it’s been a while since I’ve looked at Bernal’s stuff, and you won’t find it on e621 since he is strictly DNP, but I get the feeling that’s who the second is from. It’s hard to see style in such a tiny frame but I remember him having a desktop background with character similar to that and the feather style looks right to me..but the beak doesn’t. It could be Alivia (
www.furaffinity.net/user/Alivia), but I don’t see it in her gallery.
You’ve also got to get deeper into your search terms if you get too many hits; the more detailed you are, the more likely you are to miss, but I try to increase my exactness until I get a single page of hits. So, for that blue jay I’d run: avian, female, solo to start. (Avian > blue_jay because you’re going to get people who might tag it as bluebird or something else.) Obviously, though, that nets a whole lot, so I’d kick up the detail by trying: leather, lingerie, or boots (I think?). The similar character designs I found on e621 is how I figured it
may be Alivia.
(Correction! Artist is Onta, Character is Orange04; tags include: avian, bird, blue_jay, hybrid, clothed, clothing, and solo among others that would be less useful. ^.^ Yayha e621, right?)
As for the ringtail, I kick off with ringtail, female, solo. This led me to a character that looked about right, I should have trimmed out ringtail and went with stockings instead. Information: Artist, Eelytak; Character, tee.
<.<; Who knew all my hours learning the most common search terms on e621 would come in handy some day?

It’s all about picking things generic and working your way up the most likely tags until you have a manageable amount of hits; it isn’t going to catch everything that is on e621, but the efficiency gain is worth the drop is 100% accuracy relative to what’s on e621.
I'm wondering if it would be feasible to do it programmatically. Basic image comparison to the point of reasonable recognition is fairly easy these days, but you'd have to have a base of images to be searching against, so it'd have to be a per-artist tool that they ran themselves.
No, I really doubt that. >.o It’d be nice if it were possible, but since all someone would have to do is trim, crop, tilt, discolor, or resize and the search would likely fail. I mean, you could try running it through Google’s imagine search, but that’s going to be a pain in the ass. If it weren’t for the fact that the content is hidden behind a paywall, the easiest way would be do a targeted image search: <Insert Image> site:IMVU.com, and let her rip. However, since Google hasn’t indexed those areas, I just don’t see any viable way to carry this out.