Are the references in the timed tool weighted?

This is just a question out of curiosity. I feel like certain references appear so often, that I almost start to know them by heart. Not just the model, but the same exact pose, prop, lighting,... On the other hand, it can't be that the overall pool of references is just so small, that I basically know all of them by now, as every now and then an image pops up, that I have never seen before.

I have to add, that I had the same phenomenon, when I was drawing on quickposes.com. Are those just the downsides of working with an imperfect random number generator, or are some images deliberately referenced multiple times in the pool?

No image is weighted heavier than any other. I think this is indeed just weird luck of the draw stuff.