Hi Harry!!!
Creating animated GIFs is about the ONLY thing I can do reasonably well with Gimp.
You do that by opening series of images at once and requesting that they be opened as layers. Then you can save (export) as a .gif file, and it will give you the option to save all the layers as an animation. It will also give you the ability to specify the timing and the replacement mode for each image (replace or overlay). There's also a syntax (that I don't remember) to add a unique timing for each frame if they need to be different.
Your idea for upgrading the site to be more HG specific is really a great one. It's been on my list for a long time. But matters of taste can be tricky to decide since different people have different ideas of what looks "professional" or "friendly" or "appropriate" or ...
Since it's a matter of taste, we could make different themes available, and people could choose their own theme that they would see when logged in. But we'd still have to decide what the site should look like to people who are not logged in. That's the tricky part, and it might be a good topic to bring up for the Board of Directors (currently a "Trial Board of Directors"). So before you do any work on it, let me start a topic for this in the Board of Directors area and see what everyone thinks.
P.S. I just posted a suggestion that the Board of Directors discuss this:
viewtopic.php?f=42&t=2023
We're still working out our procedures for bringing things up to the Board, and our current process allows any member to post topics for the Board to discuss in that location. It's up to the individual Board members if any of them wants to bring it up as a topic of discussion for the Board. Those discussions are held privately with the understanding that the discussions will be made public once a decision is reached.
I'll give the other Board Members some time to post their own ideas before I make my suggestions, but I suspect we'll want to develop a prototype that we can vote on. An easy way to do that would be to just screen capture various forum pages (like the home page, a subforum page, and a topic page) and draw directly on to them. Just draw over what we already have and post your suggestions.