For making thumbnails I use Easy Thumbnails (
http://www.fookes.com/ezthumbs/). That's a freebie that does a good job I find.
For compressing I use Jpeg Imager (
http://www.v-methods.com/).
This is a cheap proggie (25$) with a lot of functionality: compressing, resizing, several image corrections (even level the histogram). It also has batch options. It's easy to use and it gives a good result in most cases. I think the compress in combination with it's clean up filter is hard to beat.
It's not Photoshop of course, but it cost less too.