This 'N That

Downsize is a simple Mac app for batch processing images before uploading them to the web. With Downsize you can resize, add watermarks and even add frames to your images. It also integrates with iPhoto, so you can process whole iPhoto albums at once.
If you take a look at my photo albums, I used Downsize to resize the images to 580 pixels, and add the watermark.
Downsize is shareware, and is totally worth the $19.95 they’re asking for. A free limits-free trial version is available.