In the cmake-build-debug folder we have three bitmap image files called image0.bmp, image1.bmp, image2.bmp and image3.bmp, and the code asks us to name one of them as input.
After naming the file, the program creates 4 files in the same folder called image.bmp, contrast.bmp, hollow.bmp and rotate.bmp, the first is a copy of the image file and the second is a copy with a higher contrast and the third checks the 9 pixels around a pixel, and if they are all black, whitens the middle pixel and the fourth is for photos that have square dimensions, such as image3.bmp, which is a 90-degree rotated output of the original photo..
There is a complete sample of the work in the same folder.