I just got an email notification and while I can understand that they're doing this (all those GB must add up to a significant cost), the relatively short notice seems unnecessary.
Image retention is 6 months though, so it seems slightly unclear if the timer starts counting from today or from Nov 1st.
Best to assume the worst but still plenty of time to write a cron that pulls all your images, assuming for some reason you need images you don't pull for > 6 months.