I use imgur.com but you have to "learn" how to use it. If you post a (private) photo, because it's some kind of social site, you can open the image in a new tab with a right click in windows/google chrome. THEN you have a URL that you can insert into RGO with the little picture icon thing.
I put almost no effort into resizing them for the forum so they are always fricking huge pictures, resolution wise. If I thought about it I would use IRFanView to resample/resize the photos for posting but I guess it's not that important so I'll probably keep posting oversized photos from Imgur. You could use IRFanView to get a pretty small size for a direct to RGO upload also, if you want to use johnkenn's data. Just pick a small resolution, and a very lossy compression for the JPG, it would be a small file.