The program was intended for Windows operating system and the image supplied is from a Linux operating system. In the code, the images are referenced using lower case file extension, ex: 'boxRed.png', while the file have uppercase file extensions, 'boxRed.PNG'. Linux appears to be case sensitive, so the files are not found, but on a windows system, the code works just file.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
The program was intended for Windows operating system and the image supplied is from a Linux operating system. In the code, the images are referenced using lower case file extension, ex: 'boxRed.png', while the file have uppercase file extensions, 'boxRed.PNG'. Linux appears to be case sensitive, so the files are not found, but on a windows system, the code works just file.
corrected bug with revision 14. See comment for more details