the only reason I asked is because there are several of us here who can help you with resizing avatars
but you have to be able to upload and post them for us to help with the resizing
we'll all help, in any way we can!
to add an avatar, go to SETTINGS in the top right corner
then on the left, look for EDIT AVATAR
go to CUSTOM AVATAR, option 2, click on BROWSE, find the avatar on your computer, click on it and click on OPEN
then click on SAVE CHANGES in the bottom right corner