In my answer about Affine Transformations I made some little illustrations to help the explanation.How do you make an upload-able PNG quickly which expresses a geometrical or mathematical idea?This question was contrived to support my postscript answer but is intended to solicit other solutions that may benefit the SE network more generally. But for credibility, an answer must link to a post where this technique has in fact been used, as well as a sufficient howto portion if it involves more than something obvious like Select export from menu.There are two meta questions here and here concerning how to scope this question in light of the precedences it may set for our site.
How to produce simple 2D illustrations to accompany geometry answers?
2d