Benefits of HEVC, HEIF File Formats in High Sierra and iOS 11

And now there is free app, HEIC Converter, that allows you to use the new format, but easily convert images back to JPEG.

My iPhone SE doesn’t even show the heic/jpeg setting because of the ‘old tech’ A9 chip inside. So would anyone be willing to put a real iOS 11 heic image online for me to test with? I tried to find sample images online, but my queries didn’t bring up any.

I’ve found a ‘older’ sample HEIC file online, at a MacRumors forum thread (DerfBWH’s iPhone 7 Plus running iOS 11 Developer Preview 1).

macOS 10.12 Finder recognizes it as a HEIC Image, but won't render it, no thumbnail preview, no QuickLook.
Preview 9.0/iPhoto 9.6.1/Photos 2.0 on the desktop won’t open it.
iOS 11.0.3 Safari 11.0 recognises the High Efficiency Image File Format, but it won’t render it.
If I save the HEIC image to the iPhone photo library, the iOS Photos app show it fine, but is it HEIC or JPG?
This image (saved to the photo library on my iPhone) is seen as JPEG when accessed through the desktop with Image Capture/iPhoto/Photos.app . Perhaps, the file saving created the converted image, but I have no way to check that, I think?
If I save the HEIC image to the iCloud Drive and view it on the iPhone from there, the image gets distorted (3:4 portrait stretched to 4:3 landscape).
If I save the HEIC image to the iOS Air Transfer+ app, and try to view it on the iPhone from there, the image displays fine.
If I save the HEIC image to the iOS iZip Pro app, and view it on the iPhone from there, the image displays fine.
If I save the HEIC image to the iOS Phone Drive app, and try to view it on the iPhone from there, the image not loaded.
If I save the HEIC image to the iOS USB Drive app, and try to view it on the iPhone from there, the image not loaded.
If I convert the HEIC image to JPG using heictojpg.com, then I get an image of almost the same byte size (103.5%).
If I try to convert the HEIC image to JPG (or PNG) using iMazing HEIC Converter, then I get an error (Conversion Failed. Error receiving an AV frame (-35)).
If I get the JPG version from the Photo Library, then I get an image of double the byte size of the original (230%).