If I have dragged some photos together on my timeline, if I move them around too much, or zoom in they start to get all buggy. The first frame of the photo is of another photo, and it doesn't change even if I crop it or shorten it, and if i delete it, it moves to the next photo. It's a nightmare. The video is of only 2 photos but a third flashes up in the middle.
I'm not a mac guy, so not sure, but look around here or the web to see if you need a video driver and / or update. Hopefully someone else will see this and can help. You can also try a brand new project, copy the photos to a different name, and use those give it a shot. Maybe before this do this:
• Start PP from it's normal desktop icon (IE: don't open from a project file link). • Close the Open/Home screen (and you will be in PP without a project open). • Go into Edit/Preferences/Media Cache (Mac users adjust menu name) • Then Press: Remove Media Cache Files: and Delete... • Select: Delete all media cache files from the system and OK • Close PP - It will create any needed cache files on the fly as you edit.