what if we recognize a photo so much that we can look back and see a similar one in a different challenge? I assume that's acceptable since I know they are not the same image, just the same subject.
There's nothing "illegal" about using to (virtually) identical photos, so long as the shutter open and closes twice and you use the two separate files. As your post indicates, though, it might not be a wise choice if one is seeking higher scores.
Some things (e.g. Golden Gate Bridge) will show up taken by many people ...
I've had that feeling several times in the last 2 challenge I've voted, saying to myself "Hey, this could go in the next challenge" or "Hey, this must be a leftover from the last challenge". Maybe I've just been looking at too many pics lately.
