To resize images using the right-click menu, you used the Image Resizer PowerToy to resize images from the right-click menu in Windows XP. The Image Resizer PowerToy which was originally written for Windows XP, does not work in Windows Vista. However, there is a similar tool available for Windows Vista, written by Shahar Prish of Microsoft.
Resize Images using the Right-Click Menu
Download Prish Image Resizer (for XP and Vista 32-bit) and install it.
Prish Image Resizer adds the two options "Copy Picture" and "Prish Resizer" to the context menu for image files. The "Copy Picture" option copies the image to the Windows Clipboard. Selecting the Prish Resizer option will bring up a dialog:
Select the appropriate size and click Resize.
VSO Image Resizer is integrated into the Windows explorer shell, right click on your pictures and start working on your pictures! It can also change file names using a template and you can add your own watermark with transparency support.
Resize photos in Windows Live Photo Gallery – Windows Vista Help.