Well yes and no. I think mostly it’s up to you to determine if the model is good or not. .here is an example.

I wanted to make a model and I needed a female face. (A mask). I found one in creative commons. When I attempted to use the face/head model I realized it wasn’t symmetrical. Or level. And had weird internal geometry.

I fixed those issues before I could use it for my mask model.

I figured since I did all that work and it was a nice female head, I would upload it on thingiverse so that others wouldn’t have to do through all the same trouble.

But I don’t want to just print a female head. I didn’t need one. So I didn’t. There is no photo on that upload.

It’s not really necessary.

I did, however, print the mask I made and posted photos of it with the model.

I hope my example illustrates why enforcing the photo rule isn’t going to work in all scenarios.

Just fyi. On makerworld.com, in order to upload a profile file (a pre made print file), you are required to use a photo of the model.

I think it works as a rule for that.