https://tinyurl.com/y6pvr5kj
Google Photos giving iPhone unlimited storage at original quality while
snubbing Pixel 4
google photo給iphone無限原版畫質儲存空間，但pixel 4反而沒有
"With all modern iPhones shooting photos in HEIC format, which is smaller
than even Googles compressed JPG files, iPhones therefore 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.)
現代的iphone照片是用HEIC格式，其大小甚至比google 壓縮的jpg檔還要小。iphone
因此可以得到無限的原版畫質，因為其實這樣google反而可以節省儲存空間（因為
壓縮完檔案還變大）以及計算能力（因為google不用需要去壓縮上億張照片）
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."
所以蘋果採用新的相片格式其實幫google省了很多錢，iphone使用者也因此得到原始
畫質備份
pixel 4因為還沒有辦法儲存成HEIC格式，所以照片還是會被壓縮
但android 10會支援HEIC格式，到時候就可以享受到跟iphone一樣的待遇
iphone使用者請記得不要把相片存成jpg檔，以免被壓縮