and yes, WATCHOUT 5 does narrow the possibilities - thanks
Resolutions are generally 1920x1080, but sized down the designer thought we were using HD projectors. I am outputting 1024x768. File type is mostly jpg some PNG, and yes some of the images have transparency.
If some of your .png files are disappearing,
you might want to try setting the file's Transparency specifically
instead of the default Auto Detect.
reference page 36, Chapter 3, Media in the WATCHOUT 5 User Guide
This is done by changes to the the Transparency setting in Image Specifications,
found in the media window, select the image file and open the Image dialog.
This has been known to fix some issues of disappearing images before.