Hi @ahblake!
The big-image feature is still not supported and results in strange behavior, such as displaying itext with big-image in labels and causing conflicts when saving or rendering those images. I don't recommend using big-image in Web Forms yet.
However, question types with regular images should work.
I tried the form you provided (default-image-crash.xlsx), the calculations don't work (I also got an error in Collect), but it does display the first three images.
I also tried reuploading the images, and they don't break in my version of Central. I'm wondering if the behaviors you described in your last post happened after uploading a new form version and editing a submission from a previous form version. We recently fixed a bug related to that, and it will be released soon (after wrapping up a couple of other fixes).
I might be missing some steps when trying to reproduce these issues. Which version of Central are you using?