How does JPG to ICO Converter works?
You have to upload your JPG images on JPG to ICO converter and it quickly compresses the image by stripping all the unnecessary information. All the details on your image like date of creation, location, camera settings used, etc will be deleted.
If you modified the image to convert it and get an icon, the information regarding the modification will also be gone. Only the minimal amount of pixels and data is left and then the picture is converted into ICO file format. There will be two elements on the new ICO file i.e AND bitmap and the XOR bitmap.
The AND bitmap is for setting the transparent part of the icon while the XOR bitmap determines the visible part of the icon mapped with the AND bitmap. These ICO files can be viewed on MS photos and MS paint in the windows and on Apple preview on macOS.
A lot of ICO conversion tools are free to use and provide the resulting images very quickly. The size of the resulting image can range anywhere from 16 x 16 to 256 x 256 pixels depending on the original image and the programming of the tool you are using.