While I don't actually have any solid grasp of the code that would be required, I imagine it would be possible to release 1 image to show that one does indeed have a collection of "valuable" photos. Once trust has been established that the person probably does indeed have additional photos, people will be more willing to submit bitcoin.

You overwrite each pixel of each photo with black. You assign every photo a bitcoin address and perhaps give a name describing its content (something kinky, obviously). Each photo has a set amount the person is asking for its release. As bitcoin is sent to each photo's address, more and more pixels are revealed, as a percentage of the remaining bitcoin price.

You can go further by making the first few photos far cheaper the next (potentially more sultry) photos, creating an exponential pricing system that will likely benefit the hacker. Trust is increased as a low cost photos are revealed, demand for more revealing photos increases as trust increases.

Thoughts?