The most common cause of material on the Timeline being truncated is the WAB (Work Area Bar) being set to less than the full Duration, and then Export Work Area being checked (radio button) in the Export/Share settings dialog. This will happen if one has been using the WAB to limit the area that is Rendered, or similar. This shows the WAB in an adjusted state:
If you have used the WAB, the easiest ways to reset it, or not use it, is to hit the \ [Backslash] key to zoom out to the full Timeline, and then find the little block in the middle of the WAB. Dbl-click on it to expand it completely. Or, in the Export/Share dialog, just click on the Full Project radio button.
Now, another reason for truncation can be limited HDD space. The full Project cannot be Exported/Shared. How much free space do you have on your destination HDD?
Last, you give the dpi of the images, which means nothing in video, but what are the pixel x pixel dimensions of the still images in the SlideShow? That can be very important.
Good luck, and please let us know if anything there helps,
I have faced the same issue myself and Hunt you are right ...your suggestion worked wonders for me
Thanks for reporting success. We love to hear of that!
PS - while typing just such a reply (do not recall if it was this, or a similar thread), my AC3 audio-only Export completed too quickly. I checked MY WAB and it was set for only part of the Timeline. I had used it to "measure" the Duration of several Clips for a Soundtrack, and forgot to reset it for Export - DUH!