Very nice addon, especially since it's possible to chose different categories. But there is still some room for improvement:
- Use the same font in every corner of the image (and give the user the choise which information he wants to see)
- always preload the next image. It's not necessary to see a gray background for 5 seconds before the image is loaded

Images are indeed slow to load - should store them ahead
Clock format is 12am/pm, would be nice if this could be adjusted to I could choose 24h format

The images load slowly. Maybe you can cache the next image already?