If the gap remains, then you likely have Audio beneath it, that is keeping the Video Clips from moving. If that IS the case, then hit the \ [Backslash key] to zoom out on the Timeline. Now, lasso the Video Clips (still images in your case) beyond the first two images, and with Snap ON, drag those to close that gap.
I believe that this would be much easier than Deleting the Audio, doing the Remove and Close Gap, and then dragging the Audio back to the Timeline, but the choice is yours.
Thank you so much for your prompt and correct analysis of my problem. It
was the audio that was preventing me from closing the gap. I chose to
delete the audio as I didn't have that much installed anyway. That allowed
me to close the gap.
I do have one other issue for which you might be able to suggest a fix. I
have my pictures on the Video 1 line and titles on Video 2. Then for some
unexplained reason when I reopen the project the titles have jumped to Video
3 or 4. It's more of a nuisance than a real problem but I thought that you
might have an explanation and a suggestion to keep this from happening.
I have never observed, nor read of such behavior. I can come up with no ideas on what would cause this.
Now, once one has arranged their Assets on the desired Audio & Video Tracks, they can Delete Unused Tracks (will NOT affect the two fixed Audio Tracks: Narration and Soundtrack). If one later needs to place Assets on other Tracks, they can be created to suit.
PrPro also allows one to Rename the Audio & Video Tracks, but I don believe that PrE does, though PrE 8 might have added that capability. In my case, I would probably do something like Renaming Video Track 1 to "AV Footage 1," and Audio Track 1 to "AV Audio 1." My Titles Track would be Renamed to "Titles 1," or similar. If using something like Track Matte Keying, that Video Track would be Renamed to "Matte 1." I always do this, so that I can easily and quickly see exactly which Track is which. Also, PrPro does things a bit differently - all Video Tracks are at the top of the Track display in the Timeline, and all Audio Tracks are grouped below. PrE keeps the Audio & Video Tracks together, which suits more users' needs.
Good luck, and I wish that I had some idea as to what might be causing the observed behavior. Maybe others will have some useful thoughts, but I am drawing a blank.