When a user inserts an image using the button, though there's some maximum-width scaling from what I can tell, the image can still be pretty big. This leads to some ugly stuff, and even if a user is aware of it, unless they ask for help or know where to search, they won't know how to fix it without manually resizing images themselves.
So, can the site help out? Some options:
- The insert image UI could offer a size choice.
- When inserting images larger than a certain size, detect it and tell users how to reduce them.
- Default to a definitely safe choice (maybe the "m" size) and tell users how to increase it if the image is large. (Thanks, SAJ14SAJ - this is possibly the best since it means that inattentiveness still keeps the images small.)
This is related to an old meta SO question, but I want to let our site request it too - and note that even automatically limiting to 640x640 often leaves some larger-than-ideal images.