There are indeed normally a "Huge" amount of civs when you choose a Huge map.
Sure go ahead.
As to how to do it: three part process:
1. Print Screen to take it; which will be placed in my games - beyond the sword - screen shots folder.
2. Edit the picture to get the width down to the allowed limits. I normally use paint and scale it 0.75 X & 0.75 Y.
3. Post it by hiting "Post Reply" and clicking upload files. One file per post.