What if I wanted to find DM maps primarily shaded in a certain shade of blue? The initial data could be automatically scraped from all their respective screenshots and additional tags (like gray + green) can be handled by users and it would be separate from the theme tag system.

This would not be too hard to do. The problem would be how to integrate it into the site.

Primarily, how do you search on a colour? Secondary, how may colours are linked to a map (based on the screenshot). Limiting to 4 colours seems like a max to me but I would also be happy with 2 colours.

I guess we could somehow normalise the all the results to a range of colours, then people could select a colour and all the maps that are close to that colour would be displayed.

Another option is some kind of dynamic colour picker, then maps that are closest could be displayed in descending order.

Happy to think about this some more and would like a clearer idea on how it would work before coding it up.

Alternatively, if you (or someone else) wanted to code something up and need some kind of access to the DB, let me know and I'll see what I can come up with.

Then there is always what wording do we use? "Colour" (everyone but Americans) or "color" (only Americans). I guess I could make it dynamic, but another thing to support.