You can just use MS Paint. That would probably be the easiest way, since it already comes on your computer, so you don't ned to download anything.

Click 'Image' at the top of MS Paint, and then click 'Resize/Skew'.

Try resizepic.com

In MS paint you go to edit, select all, and then you can resize it and save

thanks everyone!

That's is in photoshop. Just open it in paint and re-save it.

I'm not sure if this will help but there might be an option called 'save for web' around where all the other 'save; options are, If you have that it should let you resize it there. Hope this helps.