Can you please elaborate what issue you are experiencing exactly? Is it color shifting, resolution decrease and blockiness, something completely different? We do convert HEIC to JPEG upon upload and it may change the colorspace and bit depth when it’s doing it. HEIC generally has higher bit depth that will make photo look more realistic but JPEG can retain most of that in sRGB space but not strong highlights or deep shadows. If you have sample pictures (can upload to your account and share with me) that would help. So far I haven’t ran into issues with my iOS 18.1beta6 

 It appears to be a color space issue. I’m having trouble reproducing it at the moment but I’ll update this post when it happens again. 

 Uploading from the account page specifically seems to remove color profile data for some reason. https://os.hel1-c1.semisol.net/static-n/color-profile-test.png 

 I’m on iOS 17 though. It works fine with HEIC also from Damus. But it most likely is a color space issue. 

 Fixed for PNGs now, had issues with pngquant being out of date and with no profile support (thanks Semi for spotting it)