HELP how do i add stickers to my signature,slimmer of the month

[callear76]

hiya all can someone give me some help please, on ur signature on ur posts ive managed add my half a stone sticker but i also got slimmer of the week but for some reason i cant add it????? someone on here told me to copy hers and when i try all i get is this message

• Your signature cannot be longer than 150 characters excluding BB code markup.

please help me lol it would be most appreciated