Click on "My Bump" at the top just under the bump logo. Login if you need to and then you should see "Edit My Avatar and Sig" at the top. Click that and it will let you modify the code where you entered your siggy pic. Just change the url to be whatever your new picture is.
Mommy to Abigail Elizabeth (11/4/11) and Brady Jasper (7/2/09) my blog
Re: siggy pic
Mommy to Abigail Elizabeth (11/4/11) and Brady Jasper (7/2/09)
my blog