pdvrdt

CLI tools pdvin & pdvout, used to embed or extract any file type, up to ~2GB (cover image + data file).

*Compatible hosting sites, listed below, have their own much smaller image size limits:

• Flickr (200MB), ImgBB (32MB), PostImage (32MB), Reddit (19MB / -r option),
• *Mastodon (16MB / -m option), ImgPile (8MB), *X/Twitter (5MB + Dimension limits)

There are many other image hosting sites on the web that may also be compatible.

Image credit: @z3pio_

Demo Videos: X/Twitter / Mastodon / Reddit / Web Tool

To share "file-embedded" PNG images on Mastodon, use the -m option with pdvin.

To share "file-embedded" PNG images on Reddit, use the -r option with pdvin.
Select the "Images & Video" tab on Reddit to post your image.

*X/Twitter also has dimension size limits:-

PNG-32/24 (Truecolor) 900x900 Max. 68x68 Min.
PNG-8 (Indexed-color) 4096x4096 Max. 68x68 Min.

To correctly download images from X/Twitter or Reddit, click the image in the post to fully expand it, before saving.

To correctly download an image from Flickr, click the download arrow near the bottom right-hand corner of the site and select Original for the size of image to download.

You can try pdvrdt from this site if you don't want to download and compile the source code.

Usage (Linux - pdvin / pdvout)

user1@linuxbox:~/Downloads/pdvrdt-main/src/pdvin$ g++ main.cpp -O2 -lz -s -o pdvin
user1@linuxbox:~/Downloads/pdvrdt-main/src/pdvin$ sudo cp pdvin /usr/bin

user1@linuxbox:~/Desktop$ pdvin 

Usage: pdvin [-m|-r] <cover_image> <data_file>  
       pdvin --info

user1@linuxbox:~/Desktop$ pdvin rabbit.png document.pdf
  
Saved "file-embedded" PNG image: prdt_17627.png 1245285 Bytes.

Complete!

user1@linuxbox:~/Downloads/pdvrdt-main/src/pdvout$ g++ main.cpp -O2 -lz -s -o pdvout
user1@linuxbox:~/Downloads/pdvrdt-main/src/pdvout$ sudo cp pdvout /usr/bin

user1@linuxbox:~/Desktop$ pdvout

Usage: pdvout <file_embedded_image>
       pdvout --info
        
user1@linuxbox:~/Desktop$ pdvout prdt_17627.png

Extracted hidden file: document.pdf 1016540 Bytes.

Complete! Please check your file.

Issues:

• ImgPile - You must sign in to an account before sharing your data-embedded PNG image on ImgPile.
  Sharing your image without logging in, your embedded data will not be preserved.

My other programs you may find useful:-

• pdvzip: CLI tool to embed a ZIP file within a tweetable and "executable" PNG-ZIP polyglot image.
• jdvrif: CLI tool to encrypt & embed any file type within a JPG image.
• imgprmt: CLI tool to embed an image prompt (e.g. "Midjourney") within a tweetable JPG-HTML polyglot image.
• jzp: CLI tool to embed small files (e.g. "workflow.json") within a tweetable JPG-ZIP polyglot image.
• pdvps: PowerShell / C++ CLI tool to encrypt & embed any file type within a tweetable & "executable" PNG image