During the course of making a DVD which is a mixture of stills & video clips I found that some of the images, in the timeline, in the available media and finally in the "Create DVD menu" screen were upside down.
This usually preceeded a "serious" error which involved the program shutting down!. Although I was able to recover the file and eventually carry on to a successful project, I have no idea what I have done to cause this annoying problem.
Yes, they are all very high resolution. I wondered if this was the problem. Oddly, it doesen't occur all the time though and sometimes changing an associated transition in Premiere has turned the image the right way up. Still, sorted now. Thanks a lot.