Creating icon from image

Icons are somewhat different from other images. They usually have multiple so-called image formats and have transparent pixels. But, if you have an existing graphic, for instance, a BMP file, you can easily convert it to an icon using Greenfish Icon Editor. First of all, you should add transparency to the image. Then, you should create and edit multiple image formats. One way to simplify it is the following:

Tip: You should still modify the generated image formats, especially in small sizes and in lower color depths, so that they will look good and will be recognizable. For example, you should remove perspective when you convert an image to 16x16.