We have a great tip for you when making hot spots and you still want the background of the slide!
If you have odd sized images we recommend making these a .png file format and make them transparent.
(This is done before the image file is uploaded to Prezentor)
In Prezentor you can then do the following: Add Hotspot->Choose function->Add content and then add Image (top right corner under + Content)
Now you have your image (or you can do the same with a video) and if this is odd sized you can make the background transparent. See below
This also works if there are small lines (only 1 pixel) that is showing where you do not want it to! For instance if an image is not the intended size for a slide/presentation/hot spot.