Mermaid diagram support is still in process in our new docs system. Once it's available, the four flowchart images in elasticsearch/docs/reference/scripting-languages/painless/images/ should be removed in favour of mermaid diagrams in the markdown.

There are two parts to this:

1. I've updated the markdown source files with the mermaid script that will render the flowcharts, so those need to be enabled and the .png files removed
2. I agree with this comment that the mermaid script for docs/reference/scripting-languages/painless/images/painless-integration-points.pngs should be updated so that the graphics contain hyperlinks to the relevant docs sections. Same for this comment.

Just for reference:

Draft PR: elastic/elasticsearch#141851
Mermaid linebreak bug: elastic/docs-builder#2632