I don't know about the icons (there is an avatar section if you hit the user cp button up top and then go to edit options) but to attach a picture just scroll down on the message or response page and click the browse button under attach file. Then just pick your file and u're set. Although it says bmp is an option try to use jpg/jpeg or gif so the file isn't so huge. I prefer to write code to link files but that's another story.