automatic resizing is not clever, it uses client side java script which means you still download mb of unnessecary data and is annoying as hell when you are on lower resolutions. Using the imgsize tag is just using html resize which means the entire screen is still downloaded.
The best thing to do is use imagebam.com for hd screens, as it resizes and they seem more stable than other freehosts. Infact, imagehost which you are using gives forum thumbnail views already, its below the screen. Much better than posting big screens
