Sig help please

[Shamikebab]

Was surprised to find a warning for my sig being to large this morning. I'm trying to use this one:

Now when I check the size on my desktop it says 15.6Kb and when I check it on photobucket it says 15.6Kb...yet when I stick it in a sig it says 21.97Kb, what am I doing wrong

 

[Shamikebab]

how odd

I'm in firefox and it's still saying 21.97kb. I used the GIMP to reduce the file size as I did before. I don't really want to stick it as my sig and get in trouble :/

 

[Shamikebab]

that says 15.6Kb, how odd!