Slide image distorted when learner jumps back to Base Layer

I have a presentation that I did for class and would like to add to my portfolio. Slide 6 functions as a base layer, with 5 pictures that the learner can click on to learn more about each topic. The "layers" are actually set up as separate slides for this particular course, and the learner clicks on a Return bottom to take them back to Slide 6.  

The first image plays correctly, but when the learner clicks Return, the image on the original slide is distorted. It takes up most of the screen. I can't figure out why this is happening, and it doesn't happen with any of the other images / layers. 

 

http://s3.amazonaws.com/HDLearning_PublishedOpenly/Resolving%20Workplace%20Conflict/story_html5.html

Suggestions?

Thank you,

Heather

 

P.S. Not sure if this is relevant, but I built the course in Storyline 2 and recently upgraded to 360.