This procedure can be done simply with any Windows computer WITHOUT the needs for any professional or third-party photo editing software.
In other words, we don't need PhotoShop or any other photo editors. We can just use the program "Paint" which is provided with Windows OS by default. It can produce fairly adequate results for web-quality photo/images. Let's take a look.
1) Click the "Start" Button
2) Select: "All Programs" -> "Accessories" -> "Paint"
3) Now open your picture in the "Paint" program
4) Click on the menu "Image" -> "Stretch/Skew"
5) Now fill in the "Horizontal" and "Vertical" values (in smaller percentage than original size)
Try to reduce to '25%' and you'll see how relative your picture is compared to original size.
This is how I use the sample picture "Blue hills.jpg" resized to 25% looks like in Windows XP.
Then save your picture with a new name if you don't want the original picture to be resized permanently.