I found a bug: I had a .webm in the folder I set, and seemingly any time the game tried to load it, it would prevent the game from cycling through images. If the .webm was the first one loaded, this image would be stuck on my screen:
and if it tried to cycle from an image (from the folder I set) to the .webm, the image would stop cycling through as well.
The resizing seems to work fine, however - much appreciated.
[Edit: the image I attached would flash on my screen for a split second whenever I started the game from the menu, before it displayed the first image.]