Not to long ago I needed an image of a Mariachi for a poster.... right away I went on dreamstime and to my surprise found a very limited selection. Most were of some silly looking guy and others of a young boy wearing a sombrero (Interesting images but this is not a Mariachi).
I had to do without it and instead created my own illustration. I quickly uploaded my illustration and proceeded to create more, They are now online with dreamstime and available for your consideration.
I am happy to say the gap/niche is partially filled. I now find myself looking for such gaps to fill. It seems dreamstime is highly receptive to the type of images that they don't have.
Just a thought for your consideration. Regards!