Can you create an oil painting of any idea, even if there are no photos?
Yes, I would research images that would support your idea, if you didn't supply them. If you are specific in what you want, I could then make an illustration.
Your idea would have to be very specific or simple. Otherwise reference photos showing what your idea is are required. The artist would have to do this anyways, to get an idea of what you want, and it's easier if you browse the internet for photos depicting what's in your mind before try to find artists through Instapainting.