Unfortunately if we allowed this option then our server/storage costs would spiral out of control very quickly. In the future there will be a paid version of the forum available - this will open up many more features on here for those users, including file storage and photo albums. We will keep this cost as low as possible in order to simply break even. If I find another way around the issue before then, of course we will implement it for free for everyone.
For now, in order to keep it running for free along with our main site, we will have to use external links.
There are plenty of free file hosting sites out there though, which you can use to store specific photos you might want to share. Tomorrow I will get a list together and post them in this thread.