Check if JPEG images are progressive
Can be useful to make sure your images are progressive, which is important for performance:
Progressive JPEGs are better because they are faster. Appearing faster is being faster, and perceived speed is more important that actual speed. - Progressive JPEGs: a new best practice
The check is fast as it only reads a small part of the file.
npm install --global is-progressive-cli$ is-progressive --help
Usage
$ is-progressive <file> ...
$ is-progressive < <file>
Example
$ is-progressive baseline.jpg progressive.jpg
✖ baseline.jpg
✔ progressive.jpg
You can use globs too if your shell supports that.
is-progressive *.jpg- is-progressive - API for this package
