You should automate the process of adding new puzzles, instead of manually adding them everytime.
Why not code up a queue (and put a set of puzzles in it) so that once someone has solved the picture, or the picture has expired, it automatically publishes the next puzzle for you?
Yeap I want to do that too actually.
Here's something different:

No hint this time! Could be item/person/title or even anything else.
It looks like a head. Since it can be a person, it is most likely some Superhero from Comics or video games.