First, to check you signature, you do not need to make a new post. When a signature is changed, it is changed in every post that has the signature. (Background: Signatures are not stored with the posts, but are added when the display engine creates the page.)
I'm making a guess. You have added a rig picture to your profile and you want it in your signature. Profiles and signatures are separate things. Signatures are created and edited on your My Preferences page. (Link is found on your My Forums page, just to the left of the My Profile link.)
Second, signatures can have only one picture. If you upload the rig picture on your My Preferences page, the map will be replaced. Where you see what appears to me two or more pictures in a signature, the member has combined the pictures before uploading the one combined picture.
Also, I have a long-standing offer to combine pictures for members. (Send me a PM and I'll give you an email address to which you can send the pictures.)
