Because version of Windows (lower than the 10th version that already supports that option natively; note that the app also works with Windows 10) does not allow user to increase the size of the mouse pointer behind few pixel, it can be hard for partially sighted person to see the mouse pointer. It can be seen as a far simpler version of ZoomText which is a costly solution for people who might only want to use the mouse pointer option.
See the demo video
The scritp set an hook over the mouse move to retrieve the its position on the screen and then the app moves a transparent window with a custom image (as png/jpg/bmp) with alpha channel supported over that position.
Windows over Windows XP
Since the app uses a window over the windows mouse pointer some system windows will not allow to set that window over them. In other words, for some system windows the custom mouse pointer will freeze (and then coma back to normal when the mouse exit the system window)
The app allows user to change and rescale the image while running