Question Photobucket and size issues!

I created a picture on Microsoft Picture it Premium 10 (and some other movie making program) for my signature, but the bytes are too big to upload from my computer.

So I put it on Photobucket and put the URL for it in the signature editing space. Once again, the size was too big. How can I make it smaller without making the pixels all messed up or making it too small??

 

Try to resize it in the program you used... Try holding Shift as you do it.