How does an ICO icon make

1, first, download and install IconWorkshop software and open, here to extract from the MIUI system of a PNG picture file as an example, if you want to use the PNG image as an icon, then the system will pop up the file does not include the icon hint:

2, so the next thing we want to do is to convert it to an ICO icon, the PNG image will be transferred to the program processing box, or select the menu bar in the "file" in the "open" also line, when the picture file will be displayed in the processing box:

3, click on the image processing box in the top left corner of the first tool button, this key is probably the purpose of "a picture to create a new icon," in the pop-up window tick you want to get the size of the icon, and then click OK: