What YAML is
YAML uses indentation instead of brackets. It is a superset of JSON, supports comments, and is meant to be edited by hand.
Kubernetes manifests, CI pipelines, Ansible playbooks and most modern config files.
What PNG is
A lossless image format. Text and thin lines stay exactly as drawn, which is what a table is made of.
Slides, chat messages, issue trackers, and anywhere a table has to travel as a picture rather than as data.
What changes when you convert YAML to PNG
A YAML list of maps reads as rows and columns directly. Anchors and aliases are resolved before the table is built, so a repeated block arrives expanded rather than as a reference.
The table is drawn from the data onto a canvas rather than captured from the page, so the whole thing comes out however long it is and however much of it is on screen. Column widths are measured from the content, alternating rows are shaded, and the scale is adjustable so a table for a slide or a print layout can be drawn at two or three times the size.
What carries over from YAML to PNG
YAML records 4 things about a table that PNG has no way to hold.
YAML knows which of its values are numbers. PNG keeps only their appearance, so nothing downstream can sort or sum them without someone reading them back off the image first.
An empty cell and a missing one are the same thing in PNG, so a null and an empty string in the YAML both come out blank and can no longer be told apart.
YAML can hold a value that is itself a list or an object. PNG has only flat cells, so nested values are flattened into one cell rather than being spread across columns.
PNG is the end of the line for this data. Reading the table back out of it is a separate and much harder problem than writing it, so keep the YAML if you will need the values again.