The graphic representation of an icon is contained within an .info file.
It is also possible to replace the graphic representation of an icon or icons with Iconsets. These can be individual
or complete sets of icons developed to change the appearance or theme of Workbench.
Go here for a selection of web sites that specialise in creating Iconsets for you to install. Includes screenshot previews to help you decide which style you prefer.
Be sure to also read the authors system specification notes to ensure you meet the necessary requirements, as some Iconsets require AGA chipset, datatypes and certain Workbench version release.
You may also wish to design and create your own Iconset, so be sure to check out the Video section of the Amiga Realm Software Directory.