Absolutely. To add additional icons to your system you simply add a new directory to koha-tmpl/intranet-tmpl/prog/img/itemtypeimg/ and to koha-tmpl/opac-tmpl/prog/itemtypeimg and put your icons in the new directory. Your icons will show up in a new tab as soon as they are in the folders.
TIP: Remember to put the icons in both places (on the OPAC and the intranet).
Posted in: Display