PG Theme - optimize microthumb images?

I recently went through my site and made changes to lower overall page weight. One thing I had to remove was the microthumb strip I had running underneath every full size image. While I really like this feature and think it aids in navigability, the microthumb images were adding far to much weight to my pages. I noticed that no matter how large/small I set the microthumbs to appear the image size never changed. The microthumbs were around 8-10K, which are about what my larger 160-170 pixels thumbs weigh. Apparently there is no optimization of the microthumbs going on...they are just full sized thumnails reset to display at a smaller size. Is there a way to actually optimize the microthumbs using ImageMagick or GD so that they don't only look smaller, they weigh less too? Thanks! - http://andrewprokos.com/photos/new-york/