Space & bandwidth have nothing to do with it. We are talking processor activity & overall efficiency of this website - not just the forums.
It has to do with how the server fetches images from other sites.
There are many reasons that this causes drag - not to mention the secondary effects where folk will post very large images which can cause other processor problems & many sites will prevent refernces from external sites .....
The forums are a very small part of this site & we have to prioritise our main users who are using the simviation website.
addfitionally - there is no reason any 800 pixel image needs to be over 100k. You will never have any image that requires this.