If they compress screenshots like Microsoft does, or like Instagram does (73% quality JPG), they can store 4 screenshots in the space of a regular 100% quality JPG, which means 90-100 KB per. Assuming a screenshot every 10 minutes, in a span of 8 hour computing per day, each day takes up a mere 5 MB. This is close to what SOG/Mutahar demonstrated on YouTube recently, 8 MB per day. A month of screenshots is merely 250 MB. And this does not even account for MS having a LLM model to sort through screenshots and discard useless ones, which might give roughly 30% more efficiency. We are looking at about 1.2 GB storage for 6 months of screenshots.
Recall allocates 25 GB on 256 GB storage, so that is 10 years of screenshots. If MS decides they can ramp up speed of screenshots and grab even more information.