Indexhibit^TM
Index + Exhibit

I would like to put a jpg in the top-left of the left menu, above all the other menu bits. How can I do it? I'm probably being stoopid, but I don't see any upload features for that bit.

First, you need to be on advanced mode (settings).

Then, you upload the image with the file manager in an exhibit, and insert it in an exhibit. Then you cut the code for the image, and you paste it in the pre-nav input field in the settings page.

Voilà!