Works great for me on vb414. There are less requests like promised.
However I use Absolute path (
http://cdn.domain.com/forum/image/buttons vs. images/buttons) in my image_dir style vars and this plugin doesn't seem to support it when I run the "refresh".
Overall I think this is a very significant performance enhancer that VB should have built into the software about 2 years ago. Thank you for writing this add-on and keep it going.