尺寸越大的图，压缩率越高

hbghlyj

当我尝试编辑/筛选我的照片库时，看到许多图像尺寸(dimension)较大，但文件大小(size)却很小，我感到非常困惑
Why are images that have larger dimensions have smaller file ...

It's how jpeg compression works. Your bigger (dimensions wise) files were either saved with a greater compression ration or simply the contents are more compression friendly. Big areas of relatively even colour compress well.

hbghlyj

en.wikipedia.org/wiki/JPEG
压缩的目的是看起来“相同”但减小文件大小。
所以，如果图片本身尺寸很大，就可充分地压缩文件大小而使得看起来“相同”。