Yes 💯

Only upload, download is outside their control.

On Flappy Nostrich I had to implement server side compression & resizing to optimize them for game asset use.

You mean it should be configurable in a client whether it should be downloaded at all? Can't resize unless you have the whole thing, which still requires downloading it first. If you are unlucky the hosting webserver will not even tell you on forehand how big the file is you are trying to retrieve.

I never uploaded from a client. I just pointed it to a url with an existing image. What should a client do if you can't get the filesize before starting the download?

No I mean the user should never have to think about this. So either the client or connected storage provider resizes appropriately.