Nicely done, looks great!
Don’t worry about the image size too much. They could be a touch bigger, but they’re OK as they are.
You may have noticed me talking about uploading huge images. You can do that now, but when you do, the forum shrinks them down to 1600 pixels max. This saves space on the server and bandwidth. So why allow big images to be uploaded? It means you don’t have to take the time to make them smaller. You just take the photo, upload it and we do the rest. The goal is to keep quick and simple for the members.