I have been doing that for the past couple of months Since most of my reviews are repetitive images from ICO projects, I just borrow images links from others users rather than uploading them myself and quote the source as the ICO project.
Unfortunately, I don't think this can be applied to the mass, this is a personal management thingy, which is hard to control or apply on a community social network.
The best solution would most likely be a private folder onsite members could upload images to and pull from when needed, or discard when no longer needed, with storage limits that would increase with the amount of SP a member has.