1 You need to use the ".icon" paintingmode and the "Icon" setting instead of the "Image" setting.

2 No idea. Make sure it is actually pinned?

3 Parse the path and extension with regexp (scripting)

4 I dont think 24x24 is too popular

5 No I think only magic pink can be magic (with the correct settings ofcourse)

6 Simpler module? Not that I am aware of. Texteditboxes are pretty simple though ;)