I am iterating through images on a 3D image widget. With each step in a .pvz sequence I change an image accordingly. I noticed that capitalization of file extension can cause issues. In the Studio preview, it is fine, but after you export to an IOS device, anything image file that ends in .JPG instead of .jpg doesn't show up.
I think this is a glitch, since they should be treated the same -- but at least now I know what to avoid when generating images for my app.