Not to wikipedia, to our wiki, which runs on the dokuwiki engine. When you open a page to edit it, there should be a button in the list of editing options for the page that looks like a picture frame. When you highlight it, it should say "add images and other files", and when you click it, it will open a second window with a place for you to browse to the photo on your computer, and then upload it. You'll want to upload any images for this character to the independant root, not the main root.
Again, though. Unless you own the rights to the image, please do not host it on our wiki. We'll have to remove it.