postline

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Your graphics library

out/cards/ is a working folder: it is overwritten every time a card changes and is usually not committed. So postline also keeps a library: a folder on your own computer with a full-quality copy of every card it renders, ready to reuse in a deck, a website or print.

By default the library is at:

System Folder
macOS ~/Pictures/postline/<brand>
Windows C:\Users\<you>\Pictures\postline\<brand>
Linux ~/Pictures/postline/<brand>

<brand> is your brand name in lowercase with dashes, e.g. nsisong-labs.

What gets saved

Every time postline render or postline publish renders a card, the library gets:

  • 2026-11-02_launch_3f9a1c2b.png: a lossless PNG at 3x (3600 x 3600 for a square card) regardless of the size you post at.
  • 2026-11-02_launch_3f9a1c2b.json: the post text, per-channel variants, topic, alt text, layout, size, source file and, once published, where it went with links.
  • index.html: a gallery of everything in the folder. Open it in any browser; no server or internet needed.

The last part of the name is a fingerprint of the design. Edit a post's card and the new version is saved next to the old one, so earlier versions are never lost. Re-rendering an unchanged card doesn't write anything.

Posts that use your own image: instead of a card are copied into the library when they are published.

postline library          # where the folder is, how many cards, the latest ones
postline library --open   # open the gallery in your browser

Exporting at other sizes

For a one-off copy at a specific resolution, size or format:

postline export launch --scale 4                       # 4800 x 4800 PNG
postline export launch --size landscape --scale 2      # same card, landscape
postline export launch --format jpeg --out ~/Desktop/launch.jpg

Exports go to <library>/exports/ unless you pass --out.

Settings

library:
  enabled: true                        # default: true, except in CI
  dir: ~/Pictures/postline/acme        # ~ is your home folder; relative paths are from the project
  scale: 3                             # 1 to 4; 3 = 3600 px wide for square cards
  • In CI (when the CI environment variable is set) the library is off by default, because the machine is thrown away after the run. Set enabled: true to keep it anyway, for example to upload the folder as a build artifact.
  • postline render --no-library skips the library for one run.
  • If the folder can't be written (a full disk, a missing drive), postline prints a warning and carries on. Rendering and publishing never fail because of the library.
  • The library lives outside the project on purpose, so it is never committed and survives deleting or re-cloning the repo. Back it up like any other folder of pictures.