I don't know who is in charge of web programming there at Portalarium but, as you can see in the screenshot below, the banner at the top of the forum is cut in half on my phone.
I think adding that banner in the forums is a great idea - especially since you need to login to shroudoftheavatar.com nowadays to see the content - a lot of people probably go right to the forums and might miss an important announcement not posted in the forums. Getting it to be a responsive web design will probably happen in the near future.
Xenforo is the forum software we use so we don't really have much control over how it displays stuff. Just getting anything to work at all is a minor miracle...
I know, it would be a lot of work, but you should consider updating to XenForo 2. Here is what I do with XenForo 2 and some AddOns: New Britannia.
Just need to add a new class at the end of the img class of that banner which contain max-width: 100%; and height: auto; miracle! ;p css always take the last css values in count, unless something else really modify the way it show (can still be overwritten in that new class)
or click on the banner which takes you to the page that has all the details and is formatted correctly...