Are all of your photos resized to no larger than 2000x1500 pixesl (72 ppi)?
If you've sized the photos on your timeline to that size and you're still having problems, please post to this forum your computer specs: Your processor, RAM and how much free, clean, defragmented space is on your hard drive.
From your screenshot, you are using Premiere Elements 12/12.1 on some version of Windows (assumed either 7, 8, 8.1, or 10 64 bit).
What is the total duration of that Timeline - is the Timeline Indicator at the end of the Timeline content in the screenshot, if so then your total duration looks like about 24 seconds according to the Timeline time readout in the screenshot. What are you doing - Timelapse video? The Timeline in the screenshot look unrendered. How does the Timeline content preview when it is Timeline rendered without going to Publish+Share? Do you pick up on any problems then?
The answers are in the details. Consequently, please consider and supply more information, for questions already asked and mine.
Please determine if either of the following applies to your situation
note the do not exceed 1920 x 1080 16:9 pixel dimensions....more on that as the discussion develops