Apple Configurator
By default Apple Configurator stores their .ipsw archives in this path:
~/Library/Group Containers/K36BKF7T3D.group.com.apple.configurator/Library/Caches/Firmware/
Files look like this:
iPhone13,2,iPhone13,3_15.6.1_19G82_Restore.ipsw
By default iTunes Updater in Finder stores their files in this path:
~/Library/iTunes/iPhone Software Updates/
Also, you can install/update custom image via cfgutil CLI:
cfgutil -v restore -I ~/Desktop/iPhone13,2,iPhone13,3_15.6.1_19G82_Restore.ipsw
Custom images you can find here: https://ipsw.me/
