I'm sure you already know, but I have to say it:
First and foremost, the loading problem is the issue that really should be addressed. I'm not sure where these images are coming from, if they're being incorrectly generated, or why they're rendering when only partially loaded, but this is ultimately the issue that needs to be solved. Users have experienced long load times and can be adequately prepared for that (loading indicators, image placeholders, lower quality images that get replaced with hi-res, etc...), but half-loaded images is unexpected, so a user wouldn't necessarily be ready to handle that.
Until you fix the real loading issue, I'd suggest simply reporting it as an error.
However your app reports errors, I'd follow the same pattern and show that some images failed to load. Provide the user with a way to trigger a reload, preferably one that requests all failed images so they don't have to find and tap each failed image.
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