This Adium plugin stores all icons that your contacts use over time and comes with a viewer for the icons.
After installation, the album will slowly fill with icons as your contacts change them.
You can open the album viewer with the Contact Album entry in Adium's Window menu and with the View Album entry in the context menu for contacts.
Icons can be copied from the album viewer via Drag&Drop.
These details are provided for information only. No information here is legal advice and should not be used as such.