First off, you posted this in the wrong section. It should have been posted in Dwimorberg. This is the RP (short for role-play) section.
Secondly, you need to sign up for a free hosting service such as Photobucket to upload your images to. Then you can copy and paste the url (which is the link to the image) and put it in the signature box (located in your profile) like this: [*img]url link to image here[*/url] (be sure to remove the * or else it won't work). You do the same for an avatar. If you had the graphics custom made, it's a good idea to credit the artist (but not always necessary). Hope that helped a bit.
Sorry and thanks