Currently, the organization of the "add to pool" menu has become far too cumbersome from within the image. It's a simple drop-down menu that comes out after you click on the "add to pool," and while it would've served fine when the number of pools were small, the number of pools have become far too great to find things effectively. Many of the pools also have very similar beginning titles, and thus it's become impossible to distinguish between multipart pools with only the last character different, as the drop-down menu cuts off after a certain length of the title of the pool.
My suggestion? Replace the drop-down with a search box. Have it trigger similar to the popular manga reader websites (i.e. mangafox.com) such that when you type in a few characters, say touhou gaoo, it brings up a short list below it that shares similarities to the input characters. Thus, you can easily click on one of the relevant pools to add the picture to the pool.
I'm not sure how difficult it would be to add this, but I'm certain there are other people who also find the current system of adding images to a pool unwieldy.
Updated by user 287254