I found this and it helped me..

You can upload using this method:
http://www.marapets.com/blogs.php?entry=230407

Images can be placed on siggies and profiles without using Marauploads by uploading them to Photobucket, Tinypic, or Imageshack.
You just need to add in an extra code.

After your image is uploaded to one of them, find the image code and copy/paste it into your siggie. The image code is the one that looks like this: [IMG]your_image_url_here[/IMG]

Beside that code put in this code:
http://images.marapets.com

You may have seen another code with the invisible gumball but this one is smaller and won't make your siggie off center.

If you want to put an image into your club layout please follow the directions on this page:
http://www.pryzmdesign.com/marahtml/tipstricks.cfm