http://developer.yahoo.com/yap/yml/image.htmlAttributes
Name Type Required/Optional Description
src string required Source file of the image (.gif, .jpg, .png).
alt string optional Alternate text associated with the image. Defaults to an empty string
height numeric optional Height in pixels of the image.
width numeric optional Width in pixels of the image.
yml:image only support above attributes. It didn't indicate it support css type of attributes. I use <div> ouside <yml:image> and it won't apply css style to <yml:image>.
Yahoo! please add more styles to yml:image