Using IrfanView to Edit Images
IrfanView is a free (for home and educational use) program that will edit graphic images. While it is not a complete graphic editor it will do the following:
resize / resample graphics (very important when creating images for email or web pages)
change color depth (from millions of colors to 256 colors, for example)
Sharpen (this works VERY well!) compare to original image
view a directory of images as thumbnails
More importantly, if you need to perform the same function on a number of images it has a BATCH mode that can apply many of these functions to any number of images automatically. This is frequently used to change the resolution of a group of images that are destined for use in a web page. If the images were shot on a high resolution camera, IrfanView can convert all of the images to 640 x 480 resolution, for example, automatically. A VERY powerful tool!
DOWNLOAD HERE or from link above
Direct download of version 3.85
Sample images: (hold mouse cursor over image for information - double click image to see full size image)