I have added buynow buttons from Paypal to my wordpress blog and on some browsers the buttons are huge. I am using a Mac and on my firefox and safari the buttons appear just fine, even on my laptop which is windows XP using IE 7 they look fine. However, IE on vista and windows 8 sometimes the buttons are huge.
PS. Can you also check the buynow buttons and see what they look like on your browser. If you could let me know your browser and whether or not it looks good or if its huge, I would really appreciate it.
One of my pages that has a button on it http://danoreef.com/blog/?page_id=5