Lost in iCloud Translation? When PNGs suddenly become JPEGs

Every month or so, I write my Genius Tips section for MacFormat magazine. Part of that process involves making screenshots on Macs and iOS devices, to illustrate most of the items in the section. As MacFormat remains proudly a print magazine, we have to prepare our screenshots to high standards, and one of the requirements is using PNG rather than JPEG format. This is because JPEG is a lossy form of compression which can readily result in artefacts and degradation when printed.

I was happily assembling my screenshots yesterday, transferring them from my new MacBook Pro, iPad Pro, and iPhone using iCloud Drive. I was taken aback to see the one shot which had been taken on the iPad Pro was a JPEG image, not PNG.

I should perhaps explain that this iPad Pro is a 9.7-inch, the last to go without hardware support for the new high-efficiency HEIF/HEIC image format, something I’m more than a little disappointed about. Otherwise, with a Pencil and keyboard it is a true delight to use.

My first suspicion was that somehow iCloud had decided to convert the image file format for me, in the way that it does for HEIF/HEIC images. Knowing that my iPad Pro couldn’t write those, this was still puzzling, so I looked back at my previous screenshots from it. The last PNG which I have from it was on 23 January 2018. The next screenshot, taken and transferred on 13 February 2018, was a JPEG.

iOS 11.2.5 was released on 23 January, but my screenshot was taken hours before I would have installed that update. So whatever has changed could be the result of 11.2.5. The next update, to 11.2.6, wasn’t released until 19 February, by which time my iPad Pro’s screenshots were coming across as JPEGs.

There’s another puzzle too: my iPhone 6 (sorry, I am going to upgrade as soon as I can find time to) has steadfastly provided PNG screenshots throughout, in 11.2.5, 11.2.6, and 11.3. So whatever has changed only affects iPads, and possibly only those with larger image sizes.

Needless to say, there’s nothing in Apple’s iOS 11.2.5 release notes to indicate any change which might have caused this. Nor can I find any mention of it elsewhere. Perhaps it’s just a bug, or my iPad Pro has turned rogue.

Or maybe it’s not the iPad Pro, but iCloud itself. When I emailed myself the same screenshot which iCloud delivered as a JPEG, the attachment was a good old PNG. Sometimes in the past I have emailed myself screenshots from iPad or iPhone, but 13 February 2018 is the first JPEG screenshot that I have ever had from an iOS device.

Perhaps – as my iMac is not an iMac Pro – my error was in not keeping to a Pro line-up, or 11.2.5 did mysteriously enable HEIF/HEIC encoding of screenshots? To test those, I checked iCloud Drive using the one Apple device which I have which definitely can process the new high-efficiency formats properly: my new MacBook Pro, with its 2.5 GHz i7 Kaby Lake processor. That also sees the screenshot from the iPad Pro as a JPEG.

As far as I know, there’s no user control over the format of screenshots in iOS – they come in PNG only, even from an iPhone X, I understand. Neither is there any user control over how iCloud Drive handles images in HEIF/HEIC or PNG formats.

I wasted half an hour trying to get one screenshot yesterday, a good illustration of how workflows involving Pro-branded products with iCloud Drive may not deliver pro results.

But later last night, in discussion with those marvellous folk at @AppleSupport, they found me a workaround, and pinpointed where the problem must lie. When I take a screenshot, then view it in Photos, tap the Share icon there, and despatch it to iCloud Drive, that image is shown as a JPEG throughout, with the .JPG extension. When I take a screenshot and immediately tap its transient thumbnail at the bottom left, before it vanishes, and despatch it from there to my iCloud Drive, that remains a PNG with the extension .png (also note the lower case).

Later today I have a call scheduled with a Photos specialist to see if they can work out whether it’s a bug in Photos, or just my iPad Pro being temperamental.

One important lesson for me is the value of the new Apple Support app available free from the iTunes App Store: I have installed this on my iPhone and iPad now, as it makes support calls so much easier. It’s a shame that Apple hasn’t yet produced a version for macOS.

Apple is beginning to remind me of a certain quality car manufacturer, who (it is claimed) achieved their high quality and much of their cost not in first build, but in meticulous defect rectification. Apple’s support is second to none, but if the bugs/problems weren’t there in the first place, and documentation was systematic and complete, wouldn’t less support be required?