Or to be really fair (devil's adocating), don't publish the name of the artist under the thumbnail in the galleries (as someone else mentioned) and don't have all those favourite artist ebot things happen... then the viewing rate (and hence hot20 ranking) will come down to just your option 1 (hopefully the thumbnail's clickability will be a good gauge as to the quality of the pic) and 3 (but since these folks view every pic, then they'll add the same view count on everything, and yeah I don't know of too many people that go through everything.... though there's a few names that seem to appear nearly everywhere and good on them for doing that).

Dreams are just nightmares on prozac...
Digital WasteLanD