Just to share.
With all modern iPhones shooting photos in HEIC format, which is smaller than even Google's compressed JPG files, while still maintaining quality equal or even better than JPG.
If you use Google Photo backup...
iPhones technically get free unlimited ORIGINAL quality backups simply because it would cost Google both storage space (because if Google tried to compress iPhones HEIC photos they would actually become larger) and computing power (because Google doesn’t need to compress and process all of the billions of photos iPhones backup.)
If a photo is larger than 16MP, it will be resized to 16MP. But iPhone have not hit 16MP yet so we are safe from it being resized
So Apple is literally saving Google millions of dollars by shooting their photos in HEIC and it benefits iPhone users as well because we get free original quality backups cause it is not being compressed at all.