Create a Rakefile in your app’s root (or add this to an existing Rakefile):

require 'your/app'
require 'tiny_png/tasks'

The rake tiny_png:shrink task can be called to shrink images from the command line. To use this rake task, you must pass a environment variable called SHRINK. SHRINK should be a comma-separated list of paths you want shrunk. As with the @client.shrink method, the SHRINK variable accepts both directories and specific image paths.

NOTE: Because this works by splitting the environment string into an array based on a comma separator, it follows that you can’t have commas in your directory or image paths.

The same constraints exist from rake as do from the method call: namely, you must supply the full path, and specific image paths must exist, be readable, be writable, and end in .png.

Examples:

Shrink a single file:

SHRINK=/path/to/image.png rake tiny_png:shrink

Shrink multiple files:

SHRINK=/path/to/first.png,/path/to/second.png rake tiny_png:shrink

Shrink a whole directory:

SHRINK=/image/directory rake tiny_png:shrink

Combining directories and specific image files:

SHRINK=/image/directory,/path/to/image.png rake tiny_png:shrink

The Rake task uses the blacklist method in building out the full paths. This method allows you to also specify blacklisted paths:

SHRINK=/image/directory BLACKLIST=/image/directory/blacklist.png rake tiny_png:shrink

By default, this rake task will use the settings in config/tiny_png.yml. You can overwrite specific settings by passing environment variables. For example, if I do not suppress exceptions in my base config, but want to when running a rake task, all I would need to do is set the SUPPRESS_EXCEPTIONS environment variable to true:

SUPPRESS_EXCEPTIONS=true SHRINK=/some/image.png rake tiny_png:shrink

You can pass in an api key in a similar way:

API_KEY=my_api_key SHRINK=/some/image.png rake tiny_png:shrink

Naturally, these can all be combined in any fashion:

SUPPRESS_EXCEPTIONS=true API_KEY=my_api_key SHRINK=/image/directory,/some/image.png BLACKLIST=/image/directory/blacklist.png rake tiny_png:shrink