thanks for adding the picture; you can use most normal commercial graphics programs like paint shop pro, photoshop etc to edit and resize images but if you dont have these then I recommend an open source (free) program called
GIMP it is a very well regarded program in the linux (free windows rival) community and a version has been made for windows.
follow the link and choose the automated installer option to download the program. once installed the gimp might look complicated but by going to the image menu and picking scale you can resize the image to meet your needs.
I have added this information as a pinned thread with further information on how to resize in painshop pro and photoshop.
I hope that this helps you.