As of now, the file handling of uploaded images is basically none. Whatever you upload is stored with no manipulation or resizing. It puts the image, exactly as you uploaded it, in a specified folder, renaming it with a randomly generated name so it will not conflict with another image that may have been uploaded with the same name (possible).

Most of our cameras now take photos at resolutions and sizes that far exceed what is needed for displaying on a web page. Great if you want to blow them up into a poster, or need to zoom in on them for fine detail, but just overkill for plopping into a forum post. I want to modify how image uploads are handled by having the server resize them into something more "web friendly" and will try to do that when I find time.

Another approach I could take is to write a script that runs periodically to resize all the images that have been uploaded to some specified parameters. That may be a better approach because a) it is easier to do and will not effect any forum code, and b) it will resize existing uploaded images to a size more reasonable for web display. 

What I don't want to do it put the onus on posters to worry about what I think should be a function of the website. Almost all modern sites (Facebook, Twitter, et al) let you upload images in whatever size or format, and they take care of everything else. 

As for resizing images yourself for web display, this is current and informative:

https://northwestmediacollective.com/blog/best-image-size-for-websites/