Creating an icon is a simple process. Lazarus can accept an 128x128 picture to convert into a icon. If the picture’s size is any larger than 128x128 an SIGSEGV error (Signal Segmentation Violation) can occur. 

GIMP or Paint.net are free applications that can be used to create pictures to be converted into icons. If you are making lots of icons, it maybe wise to look into getting an icon making or converting program.

The pictures for the Quick Clock Quizzer were created, in GIMP, by SchoolFreeware and you are allowed to use the pictures for your program.

The picture/icon can be set by using the Project Options. In order to use Project Options to set the icon, Lazarus 0.9.27 or higher must be used. Updates to Free Pascal and Lazarus can be found at: www.freepascal.org

For more information on application icons, please see the Application Icon Wiki:

http://wiki.lazarus.freepascal.org/Application_Icon

The code for the Quick Clock Quizzer can be download on the Tutorial 32 page

Video: Free Pascal Tutorial 31 - Adding An Icon To The Application - Quick Clock Quizzer - Lazarus