I found a picture that I'm pretty sure no one has uploaded yet, and considering his art style I hope the janitors recognise him and not delete it for not meeting minimum quality standards despite his art being widespread on this site (it's not likely, but there's a chance).

Though, I'm confused about the tag what you see rule when it's applied to Weaver's art. He uses colored lines (rather than filling color) to show things like skin color, hair color, etc.

For example, in the image I'm uploading is of a blonde-haired gator in a bathroom. Instead of filling her hair with yellow, he just uses yellow lines to imply that her hair is blonde.

So, if this is how he does things, would it be wrong for me to tag things such as blonde_hair, green_scales, etc.?

You don't tag anything with skin, fur, scales, or feathers unless you see it as a texture. This is a very common mistake, things that have fur doesn't get any fur tag unless it shows the texture of fur, namely patches of fur or an actual fur on the body.

Hair, on the other hand, is obvious: if it looks like hair, it gets tagged has hair.

Also, provide a source or check with Harry.Lu to make sure you are correct in that it had not been uploaded yet. Harry'll show you if it has been uploaded by % of similarity, which'll also let you see edits or resolution differences. If it's 99%, chances are it is the exact same.

The_weaver. You can also just tag TGWeaver and it gets aliased to the_weaver for you.

As for the in-image traits, if that's all you actually meant (In which case... Misleading title), Siral answered that pretty well.