Here is a short tutorial on how to get your Player/Avatar's Image.
First of all, Log on to Roblox. Easy as ever, type in your Username and Password and Log in! Then go to the Menu and select "Profile". Scroll down until you find "Currently Wearing" section. Right-click on your Avatar's Image and click on "Save Image As...". Name your Avatar's Image on your Wikia username and save it in your designated folder and you're all done!