Transparent PNG files not working on iPhone
I frequently use PNG files in photo editing apps on my iPhone. I started having problems with my PNGs a month or two ago in which half of them no longer show a transparent background when imported into my photo editing apps. I don't exactly know what went wrong or how, since images that previously displayed a transparent background suddenly don't anymore. I even exported them to my computer, to iCloud Drive, then back to the Photos app to check if they were still PNG files and didn't somehow convert themselves to JPEG, but they still were. When I exported them, they appeared having transparent backgrounds, but when I sent them back to my phone, they were white. Does anyone have any idea what's happening?
EDIT: I sent some of my PNGs to iCloud Drive and found that they somehow turned into JPEGs. However the PNGs that I sent to my computer and back to iCloud Drive and still displayed transparency, I saved those to my Photo Library (which showed that they were in fact PNGs) then reuploaded them to iCloud Drive only to find that they had been converted to JPEG upon saving. This doesn't always happen to my PNG files as I recently have been saving PNGs that work just fine so I don't understand the issue.
[Re-Titled by Moderator]