I'm suffering too.
If you use imgur to host images you can upload your images full rez but handy dandily resize/thumbnail your images for posts by adding an s, m, l or h to the end of your link. (eg. http://i.imgur.com/xxxxxxxm.jpg)
I usually size my images for computer users. Sorry mobile users! But like kup said, what is big or small really is a matter of perspective. Someone with a 4k monitor probably finds all the images to be woefully tiny.