How to Make ICO Files in Photoshop on a Mac. Images that are used as icons in the Windows operating system must be saved in ICO format. By default, Adobe's Photoshop image-editing program does not ...

The ICO file plugin for Photoshop from Telegraphics supports transparency when converting GIFs or PNGs to icons, but you must save your icons as layered RGB images in Photoshop 6 or later, ...