Important

Make sure that you are aware of pdvrdt compatible platforms, their various size limits and other posting requirements.

Default supported platforms (no checkbox) with data size limits:-

The payload (data file) is stored in an IDAT chunk, after the last IDAT chunk of the image data.

Flickr     (20MiB) | ImgPile    (8MiB),
ImgBB      (20MiB) | PostImage  (20MiB),
*X-Twitter (5MiB).

*X-Twitter also limits image dimensions, depending on the PNG colour type:-

  • PNG-32/24 (Truecolor) — 68x68 min, 900x900 max.
  • PNG-8 (Indexed-color) — 68x68 min, 4096x4096 max.

Other platform support, enabled via the checkbox options:-

  • Mastodon (16MiB). The payload is stored in the iCCP chunk of the PNG cover image. These images also remain postable on X-Twitter, when they fit its own limits (~10KiB iCCP chunk and supported dimensions).
  • Reddit (varies by cover image). This option enables a steganography method compatible only with the Reddit platform. Its storage capacity depends on the cover image you choose. Use the Capsize feature to check your image for available storage for this steganography method.

More details can be found within the README page of the pdvrdt GitHub repo.

Important

This feature analyzes the storage capacity of a cover image for the Reddit conceal checkbox option, which uses the advanced steganography method of content-adaptive LSB matching with Hamming-code matrix embedding.

The other platforms have fixed size limits that do not vary with the cover image, so there is no need to measure for them.

To maximise capacity for the Reddit method, use a cover image with large dimensions: 1024x1024, 2048x2048, 4096x4096, 8192x8192 (max), etc.

Image quality is not important for this method, and keeping it basic helps minimise the cover image file size, which is more important the higher the dimension size.

Your image is only measured. Nothing is embedded, altered or kept.

Important