Here's a really useful utility from Microsoft. In fact, this is so useful that you can almost forgive Microsoft all their previous sins.
If you regularly post photos on a Blog or website this utility is for you!
You need to be using Windows XP (anything less won't work), once installed you simply highlight the picture/s you want to resize then right click on the selection and click on 'Resize picture'. A dialogue box appears giving you options from which you choose what best meets your needs. It really is that simple!
Click on Picture Resizer to download this amazing utility.