Format for the photos

123XYZW wrote:

And why JPG but not JPEG

As far as my knowledge goes, JPEG is used by Apple and JPG by Microsoft because there was a time when Windows could use only three-letter file extension so they cut short JPEG to JPG.

Still image formats for iOS device.

• BMP
• GIF
• HEIF (requires macOS High Sierra 10.13)
• JPEG
• PNG
• PSD (merged and layered)
• SGI
• TIFF
• TGA
• OpenEXR

Did you share or upload this image anywhere?

That is probably where the image was edited to JPEG. I think you'll find both formats on the Air.