Picture settings do not save but automatically revert

Question

In PTXprint 3.0.18, I am trying to place two illustrations for a single book by modifying the parameters under Details for each image. Several parameters do not save but revert to default settings as soon as I click away from the Details tab, whether clicking Save or not: Frame Size, Vertical Position, Horizontal Position, and possibly others. For example, if I try to set them to "Column Width" (Frame Size), "Cutout" (Vertical Position), and "Outer" (Horizontal Position) and hit Save or Print (Make PDF) or both, the pictures may or may not show according to the parameters and more often than not revert to default settings. I have tried reinstalling PTXprint and modifying directly the corresponding piclist file to no avail. Is this a bug or am I missing something?