Resizing pictures for use on the Internet is a very easy to do once you have the correct tools for the job. This is the system I use I can’t guarantee it will work on your computer, or with your pictures. This is a tool for Windows XP.

Firstly you need to download and install the Microsoft Picture Resize tool – its free and simple to use. To download and install click here, you will be taken to the Microsoft website. Scroll down and look for and click on the Image Resizer link in the right hand column.
Depending on your computer and internet browser you will be prompted to save or run the program. Use whatever method is appropriate for you, for most people that will be run.
You may get a security warning depending on your computer – I’m going to choose run, again.
When prompted click next. Then follow the steps though clicking next as appropriat.
When its all installed you should see this message - click finish.
Now you can start resizing images.
Now to resize a picture all you have to do is right click on its thumbnail or file name and click resize.
The Resize Pictures dialogue box will appear – choose the relevant options – when resizing for the forum, just pick small. Then click OK.
You will now have a new image file, you still have the original and a new smaller version with (small) in the filename. Use this file when posting to the forum, or other websites. When you have done you can delete the small file, but be careful to keep the original.

Alternatively

You can also resize pictures without installing any software on your computer heres one such website that seems to work well and is free http://www.shrinkpictures.com/.