The average web page is around 2MB, 60% of which is images [1]. Base64 encoding makes the size even larger. Would that compromise on higher disk usage make sense for you? I like both the OCR and DL ideas. Shameless plug, I've been working on a bookmarking service (https://github.com/crestify/crestify), and local archiving with images is something we're looking at add. Since it is something a lot of people seem to want, contributors are welcome :).

[1] https://www.soasta.com/blog/page-bloat-average-web-page-2-mb...