That looks like the script that is available from my site and Willam van Weelden's. I have never seen anyone report it has any effect on images and can't see how it would, particularly in a random way.
I am wondering it is related to path length. Check the length of the path from the root of the drive to where the image resides. If the project is held in your profile such as in My RoboHelp Projects, move it to something like C:\RhProjects.
See www.grainge.org for RoboHelp and Authoring tips
