I need a easy photo cropping.
For putting a face onto a body.
Paint can crop...anything can crop actually.
Photo! Editor will get the job done, as CAMusing suggested, or even Paint for that matter. You could also consider:
PhotoFiltre - http://photofiltre.free.fr/
Paint.Net - http://www.getpaint.net/
Artweaver - http://www.artweaver.de/home-en/
All of them offer basic to mid-level functionality and are available for free.
Before my wife...um...obtained photoshop...she used Gimp.
I tended to use Corel Paint Shop Pro 13, but I also use Gimp and find it to be very good, although its not the most user friendly menu the first few times you use it. With the Mac I use Aperture 3 now.
I'd highly recommend you give Gimp a try - It'll do everything my fairly expensive paintshop pro/Aperture 3 will! Being free is a very big bonus too!
You can also try Adobe PhotoShop Free : )