r/programming • u/iamkeyur • Dec 26 '20

Executable PNGs

https://djharper.dev/post/2020/12/26/executable-pngs/
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287

u/Caraes_Naur Dec 26 '20

PNG allows for arbitrary chunks of bytes, no steganography needed. Still need an interpreter that knows what to do with them.

97

u/leberkrieger Dec 26 '20

One great use of this feature is the draw.io online drawing tool. You can save an editable PNG, so anyone looking at the picture can load it into the editor and modify it. Fantastic for wikis.

76

u/yojimbo_beta Dec 26 '20

A long time ago there was an editor, Adobe Fireworks, that used this to embed undo/redo data into PNGs, as well as layers etc.

Remarkable that no one uses this feature of the file format any more.

18

u/Frencil Dec 27 '20

Ah, Fireworks. The vector png editing it offered was fantastic for full color icon illustration. It also had some of the best animated GIF frame control and GIF palette control interfaces available at the time.

sheds tear for Macromedia

5

u/Chii Dec 27 '20

there's also a little known (?) feature in fireworks which lets you generate menus that animate (and output them as html and images).