1. Squash
   
   Squash gets the first prize, because it is dead simple, cross-platform (runs on Windows, Linux and Mac), light weight, super fast and can run from a thumb drive. Get it here.
   


2. Picture Resizer
   
   Picture Resizer is another simple image resizing tool. It doesn't have a UI. You need to drag your photos into the executable icon. And you can also mention the width of the expected image by changing the name of the executable!. Get Picture Resizer here.
   


3. Multiple Image Resizer:
   
   The name sucks, but the software doesn't. And yes, it does what it says, in addition to a lot more things. It resizes, adds text, adds overlay images, crop, rotate, flip folder full of images in no time. Did we mention that it can batch resize images? Unfortunately, it's built on top of .NET platform and hence is Windows only. Get it here.
   


4. Microsoft PowerToy Image Resizer
   
   Install this one and then you can right click any image and select Resize Pictures. This is really user friendly and at the same time provides ample options for an average joe user.Get it here.
   


5. High Quality Photo Resizer:
   
   Another feature rich batch photo resizer. Features: Windows only, works well in Vista, numerous input and output file formats, supports about 37 effects that can be added to your photo. Get it here.

Which one is your favorite? Did we miss out any great image resizer? How do you do the same in Mac and Linux? Please share in the comments.