Here is how you put an image into your signature.
1) Be connecting to the forums via a full web browser (not an app and not on the mobile skin)
2) Log into the Forums
3) Go to the "Settings" tab in the upper right (or click this link http://www.spacetimestudios.com/usercp.php)
4) Go to "Edit Signature" from the left Navigation bar
5) Scroll to the bottom of your signature and use the image uploader to upload the image you want to use in your signature, or put the URL of the picture you want to use.
6) in the text area of your signature put the following codes where you want the signature image you uploaded in step 5