This is for people who want to know/dont know how to put up signatures.
Most likely...the reason you need bigger sizes is because you upload if from your computer. (Like when you click on "Browse" and search for your image)
But the better way to do it is put this:
[IMG] the link of your image goes here [/IMG]
If you do not know how get the link of your image...I suggest
ImageShack® - Hosting ANOTHER/DIFFERENT WAY
Go to quick links, and click signature.
Note: This step is for signatures, which is optional.
Now click "Insert Image".
Insert the URL (adress) of your picture, and click "Ok".
Very very simple steps to put a picture of an image on.
SIMILAR STEPS GO FOR AVATAR (try not to use animated unless allowed)