GIMP is free to download and is an amazing software, comparable to Photoshop -
http://www.gimp.org/
Here's a tutorial to show you how to resize in GIMP, very simple -
http://www.gimp.org/tutorials/...
Only for MAC users there is a free program called Affinity Photo -
https://affinity.serif.com/en-...
Paint Shop Pro is an exceptional photo editing software very comparable to Photoshop but with an easier learning curve. I have been using PSP since the first version and it is a great software.
-
http://www.paintshoppro.com/en...
