Comment by zdragnar

https://stencil.so/blog/snapcompact - some agents (notably oh my pi, i forget which others) come with snapcompact as a primary means of compaction. Take the entire context, stick it in a small font in a PNG, and vision capable models can summarize and pull out the most useful information in many fewer vision tokens than the original context used.

I've not used it myself, but it's there.