Every time one restarts Locator by running stop-saga.ps1 followed by saga.ps1, any non-used Locator related docker images will automatically be deleted. This is normally a good thing as it prevents the C drive (where Docker is normally installed) from running out of disk due to Locator version upgrades (Docker images pertaining to old versions of Locator will otherwise take up more and more disk space over time). However, if one for whatever reason wants to disable this feature, then add the line below to the file custom.env before running (re-)starting Locator:
AYFIE_SAGA_RUN_DOCKER_CLEANUP=false