Powerpoint images "disappear"

I have imported my 91 PowerPoint slides for a course I have developed and which I'd like to improve in Articulate Storyline

Most of the basic text is shown on the slides however while all of the images and some added text boxes are shown on the time line I cannot get them to appear on the slide.

There are no layers and only basic jump to next previous slide triggers

I have tried right clicking on the image and using bring to front - no change.

I clicked on Show always - again no luck

I have tried hide and unhiding in timeline - no luck

Also Preview from every screen produces an Send error report screen

Without being able to see the images I cannot edit the slide.