Gallery
Pictures between :::gallery and :::, one per line, become a grid that fits the page:
:::gallery min=220 captions


:::
Options on the first line, any you like:
min=220- narrowest column, px
gap=12- space between, px
ratio=4:3- one shape for all;
auto keeps each
fit=contain- whole picture, not cropped
layout=masonry- columns, each keeps its shape
captions- each picture's words in
[ ] shown under it
On this site
Pictures from Admin → Images: ; files from Admin → Files: [The manual](files/manual.pdf), or  on a line of its own for a card with a Download button.