HOWTO resize whole folder of images in a few seconds

So,
you want to resize a folder full of images but don't have neither time or will to do it picture by picture with your favorite picture editing program. There is a simpler way. Much simpler way. So simple you will not believe. :) OK let's start. First you will need imagemagick program. Open terminal and type:

sudo apt-get install imagemagick

Install it and then navigate to the folder where the pictures you wish to resize are located. Type:

mkdir resized

This will create subfolder called resized in that directory. This is where your resized pictures will be located. Now type:

convert -size 640x480 *.jpg ./resized/small.jpg

Wait for a while until program finishes and thats it. Now take a look what have you done:

convert - name of the program
-size 640x480 - size to which images will be resized
*.jpg - input pictures, it tells program to convert all pictures in this folder that end with .jpg
./resized/small.jpg - tells program to save the resized images to folder resized which is located in folder (thats why theres dot in front) in which you currently are, images are saved as small-1.jpg, small-2.jpg, and so on

Thats all. Your resized images are located in folder resized.