Mac Users - What Image Processing Software Do You Use (Like IrfanView)

Anyone now of a good (but relatively simple) Mac equivalent of something like IrfanView?

Basically something that can handle the following relatively simple tasks (and do them well):

* Cropping
* Resizing
* Save for web
* Bulk File Conversion (not essential)

It doesn't need to be able to do anything else such as actually editing the image itself (ie: photoshop is way overboard for this) and shouldn't be resource hungry (eg: gimp).

Any suggestions from you Mac users out there? It's for the wife who's a macophile..

Have you tried: http://pixlr.com/

It's basically a web-based version of Photoshop.