Security · Browser-first processing
Encode mode writes a length-prefixed message into a newly generated PNG; decode mode checks for the ImgNimble marker.
Select a supported file or enter the requested values, then run the tool.
Closing or refreshing this page clears the selected files and generated result. Downloaded files are created as new copies and never overwrite the source.
Common questions
Steganography Encoder and Decoder reads the selected input into browser memory and performs its documented operation on this device. It does not submit the source file to ImgNimble while using this browser-first workspace.
A PNG carrying a hidden message or extracted text from a compatible PNG.
Steganography is not encryption. Recompression, resizing or social-media processing will usually destroy the message, and a determined analyst may detect it.
Practical checks
Encode mode writes a length-prefixed message into a newly generated PNG; decode mode checks for the ImgNimble marker.
Keep the source, download the Steganography Encoder and Decoder result as a new file, and verify dimensions, transparency, colour, metadata and visual detail before replacing any production asset.
Continue the workflow
Convert a local image to a data URL or turn pasted Base64 image data back into a downloadable file.
Re-encode an image locally to remove EXIF, GPS and most ancillary metadata before sharing.
Compare two images with overlay, split and pixel-difference views plus a changed-pixel percentage.