DrPic Batch Resize
The PicResize Batch Resize Tool allows you to resize multiple pictures at the same time. All your resized pictures will be returned in one compressed zip file.

Select Multiple Pictures:

Choose New Size For All Pictures:
Make all my pictures: 75% smaller 50% smaller 25% smaller

Save As:    

The Batch Resize Tool is currently in its very early experimental stage.
Known Bugs/Issues: Uploading problems in FireFox on the Mac.