zimbra - signature - to big logo

[nagileon]

Hi there
One of my users is having difficulties with the signature.
The problem is that when she attaches the signature to an e-mail the logo looks normal (small) but as soon as the e-mail gets sent both in the "Sent" folder and in the recipient's inbox the logo from the signature looks huge (takes half a page).
She's using webmail, i tried to send a test e-mail from several browsers but it's always the same.
Any idea how to change that ?
Peter