Hey bmandavia,
Just to make sure that we're on the same page, are these images that are downloaded online or are they images you uploaded from another device? Did you already try restarting your Mac? Shut down or restart your Mac
We also recommend that you try force quitting the Preview app, and then reopening it to see if it helps:
1. Take either of these actions:
Press these three keys together: Option, Command, and Esc (Escape).
This is similar to pressing Control-Alt-Delete on a PC.
Or choose Force Quit from the Apple menu in the corner of your screen.
2. A Force Quit window opens. Select the app that you want to quit, then click Force Quit.
If the issue persists, try opening these images while under safe mode: How to use safe mode on your Mac
These steps can help us further isolate the issue. Please keep us updated with the results.
Cheers!