Re: Strange image-border in IE7
Since border-style defaults to 'none', PIE collapses the border space. So you have to set border-style to something else. I actually think PIE's behavior here is correct according to a strict reading of the CSS3 spec, but other browsers behave differently so I'll likely change it to match the other browsers in the future.
Due to another bug you have to set border-color:transparent as well, or PIE will render the solid black border. That's a known issue.