This is expected, I think that images with an alpha channel don't have borders. I have listed the GNOME bug for this here, but this is a very common complaint. (I filed one about this myself actually)
** Bug watch added: GNOME Bug Tracker #355107 http://bugzilla.gnome.org/show_bug.cgi?id=355107 ** Also affects: nautilus (upstream) via http://bugzilla.gnome.org/show_bug.cgi?id=355107 Importance: Unknown Status: Unknown -- Nautilus thumnails - Not all thumbnails are created equal https://launchpad.net/bugs/59741 -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
