Just so we're all on the same page - we have plenty of space on our server - more than we will ever use.
When you post an image in a Forum, the image does not reside on the Stovebolt server. It resides on the server to which the url you provide points. (This is why some images fail - the provider doesn't allow "remote" links.)
The problem isn't space. It's bandwidth use. We pay a certain amount per month for a specific amount of bandwidth. If we exceed that bandwidth, the cost increases.
So far we have not come close to exceeding our bandwidth, but if posting large pictures in the forums becomes a widespread practice, we could.
The problem with pictures, when you use the IMG tag, is that they cost us double the bandwidth. First our server has to fetch the image in order to display it to you. Then your browser has to fetch the image from our server. So a 2MB image costs us 4MB of bandwidth. That is what we're trying to avoid by asking you to post links rather than images.
If you use the URL instead, then your browser fetches the image directly from the site where it resides and our bandwidth is not used to display the picture.