Hi Rob.
For images to work on Ultritouch, you'll want to make sure that all URLs for panel assets (images, scripts, includes, etc.) are relative to the CustomPanel. The easiest way to make sure of this is to have the assets either in the same folder as the CustomPanel or in a sub-folder inside the same folder as the CustomPanel.
I have just created a panel with image assets and verified that uploading to Ultritouch is working.
Here is how things should look:

Here is an example that will not work:

Please let me know if this clears things up - otherwise, we can debug further.
Cheers.
James
#DashBoard