can i run a competition where people send in pics to enter on IS?
You could do this with Short Stack. They offer web hooks to trigger integrations. I haven’t actually hooked it up to Infusionsoft yet, but currently have a contest running on Short Stack and am about to hook it up to an IS campaign later today.
So, in terms of the information, you can upload files to a contact record (10Mb max size) and the other relevant information on standard or custom fields. I don’t think that would really be the question here, however. The questions to ask would be more along the lines of your high level workflow for the competition and what you would like to do along each step/stage of that process. That would tell you what to do (or can be done) in respect to using Infusionsoft for this.