picons are usually small graphics files / icons that are used to customize GUI elements on various devices, for example TVs, set-top-boxes where they are used to assign custom icons for individual TV programs. These are usually just renamed GIFs or JPEGs, not really in some kind of special format, just using specific file extension and pixel size.
This means that you do not have to look for a specific software in order to make or convert them, just use any graphics editor, set them to correct resolution and change the extension once saved.
Updated: July 21, 2023