I tried re-uploading old pics I'd uploaded successfully and that worked.

I tried grabbing new pics from Flickr and Facebook groups and they uploaded.

Then I tried using the Choose from Gallery and Edit option in Summit and cropped one of the trouble causing images a smidge... and then it will upload.

I feel like I've been able to upload some higher megapixel photos occasionally in the past, and the new photos were taken with my Pixel 7, so I don't know why they would have any type of formatting issue.

This seems to narrow down the source of the problem greatly, but not sure yet what the exact cause may be. Anything jump out at you with this new debugging?