Earlier quoted context omitted.
If you don't want those writes to a block device to happen, then you could store your images in a tmpfs instead.
But then you have to provision space in memory for the whole image size or else you'll need to spill the excess on disk, even those that are not technically dirty (binaries and libraries and support files meant to be just read, I.e. likely most of the image) Demand paging the bits you actually use from the network solves both the problem of not even loading cold pages, but also the ability to throw away least recentl…
No, you can have your container system load parts of the image on demand into that tmpfs.
That's my point: this doesn't have anything to do with writing to memory, writing to block device, etc. etc. This is just a matter of indexing the image so that it can be lazily loaded. Which is of course good, but let's be clear that it's orthogonal from whether you stick the images on local disk, stick them only in memory, or whatever.