Looking very good for a first attempt Have some rep for the Map-In-The-First-Post thingy
As for critique, not much I can point to, except the res is quite small and it is hard to see the details. The one thing that I do see, is maybe bring the foothills more to the fore. As is it seems more like badlands around the mountains than actual hills. But then again, that just might be the lack of details due to the res.
A suggestion I can make is that when you are doing a post, below the text box there is a "Go Advanced" button. Clicking that will allow you to upload your map and creates a thumbnail for it too. I cannot remember offhand what the size restrictions are, but I believe that it is in the range of 4meg depending on the format. Someone with a better idea of the requirements should be able to correct me on this though.