PNG offers lossless compression, which is key in screen captures where you want to maintain accurate color and contrast above file space savings. A JPG screenshot gets more compressed, which can result in color inaccuracy, and things like fonts won’t be as clear. Since screen captures include the GUI, PNG is the best format for consistent results. For that reason, I suspect you won’t be able to screen capture in JPG.
I imported the iPad Pro screenshots into macOS Photos. Drug one to my desktop. It reads as JPEG. Maybe the desktop change converted it, or it never was a PNG. I used the iOS app iMeta to read the screenshot on the iPad Pro (10.5”). I don’t know why it said PNG.
I imported the iPad Pro screenshots into macOS Photos. Drug one to my desktop. It reads as JPEG. Maybe the desktop change converted it, or it never was a PNG. I used the iOS app iMeta to read the screenshot on the iPad Pro (10.5”). I don’t know why it said PNG.