Why do all apps require you to download a picture in order to upload it?

[Gobshyte]

Why do all apps require you to download a picture in order to upload it, when you could just copy paste??

All Pictures you find on a browser are automatically downloaded to your device, if you Copy a picture in your browser it copies the location of the picture on your device. There's only one app that seems to support copying and pasting of pictures and that is the Quora app

 

[mikedt]

The only app I do that with is WeChat, and that can copy and paste images from the browser no problem.