Like this image
It popped an error (抱歉出错了 means sorry for this mistake) when I uploaded an image for setting my website logo.
I checked the logs and storage space, and they were all normal.
Whats discourse version are you running?
there’s a fix for it, 5 days ago:
https://github.com/discourse/discourse/commit/b2b9657a0b8a64674aa0a360493dfd861b152ff6


