Stamp

Stamp is a command-line tool for adding image watermarks to JPEG and PNG files.

Installation

Download an archive for your operating system and architecture from the releases page, extract it, and place the stamp binary on your PATH.

Verify the installation with:

stamp --version

Usage

Provide an input image and a watermark image:

stamp watermark input.jpg --watermark watermark.png

By default, Stamp creates stamped_input.jpg in the same directory as the input. It never overwrites an existing output file.

Output options

Write a single input image to an explicit new path:

stamp watermark input.jpg --watermark watermark.png --output result.jpg

Process a directory of JPEG and PNG images into another directory:

stamp watermark photos --watermark watermark.png --output-dir stamped-photos

Replace exactly one source image atomically:

stamp watermark input.jpg --watermark watermark.png --in-place

--in-place cannot be combined with --output or --output-dir, and it cannot be used with a directory input. --output also accepts only one input image.

For directory input, unsupported entries are skipped. Stamp reports a processing summary and returns a non-zero status if any supported image fails.

Configuration

When --watermark is omitted, Stamp uses ~/.stamp/default.png. Override it with:

export STAMP_WATERMARK=/path/to/watermark.png

Exit statuses

• 0: the operation completed successfully.
• 1: validation or processing failed.
• 130: the operation was cancelled with Ctrl-C or SIGTERM.

Development

See CONTRIBUTING.md for development, changelog, and release guidance. The project is licensed under GPLv3 or later.