Flask-Images 2.1.1

Dynamic image resizing for Flask.

[](https://travis-ci.org/mikeboers/Flask-Images)

Dynamic image resizing for Flask.

This extension adds a resized_img_src function to the template context, which creates a URL to dynamically resize an image. This function takes either a path to a local image (either absolute, or relative to the IMAGES_PATH) or an URL to a remote image, and returns a URL that will serve a resized version on demand.

Alternatively, this responds to url_for(‘images’, filename=’…’, **kw) to ease transition from Flask’s static files.

Try [the demo app][demo_root] ([source][demo_src]), and see [with an example image][demo_demo].

[demo_root]: https://flask-images.herokuapp.com [demo_demo]: https://flask-images.herokuapp.com/demo?url=https%3A%2F%2Ffarm4.staticflickr.com%2F3540%2F5753968652_a28184e5fb.jpg [demo_src]: https://github.com/mikeboers/Flask-Images/blob/master/demo

For example, within a Jinja template:

~~~ <img src=”{{resized_img_src(‘logo.png’, width=100)}}” /> <img src=”{{resized_img_src(‘photo.jpeg’, width=400, height=300, mode=’crop’, quality=95)}}” /> OR <img src=”{{url_for(‘images’, filename=’logo.png’, width=100)}}” /> <img src=”{{url_for(‘images.crop’, filename=’photo.jpeg’, width=400, height=300, quality=95)}}” /> ~~~

Behaviour is specified with keyword arguments:

• mode: one of ‘fit’, ‘crop’, ‘pad’, or None:

  • ‘fit’: as large as possible while fitting within the given dimensions;

  • ‘crop’: as large as possible while fitting into the given aspect ratio;

  • ‘pad’: as large as possible while fitting within the given dimensions, and padding to the given dimensions with a background colour;

  • None: resize to the specific dimensions without preserving aspect ratio.

• width and height: pixel dimensions; at least one is required, but both are required for most modes.

• format: The file extension to use (as accepted by PIL); defaults to the input image’s extension.

• quality: JPEG quality; defaults to 75.

• background: Background colour for padding; currently only accepts ‘white’ and defaults to black.

Installation

From PyPI:

~~~bash pip install Flask-Images ~~~

From GitHub:

~~~bash git clone [e-mail]:mikeboers/Flask-Images pip install -e Flask-Images ~~~

Usage

All you must do is make sure your app has a secret key, then create the Images object:

~~~python app = Flask(__name__) app.secret_key = ‘monkey’ images = Images(app) ~~~

Now, use either the resized_img_src function in your templates, or the images.<mode> routes in url_for.

Can be used within Python after import: from flask.ext.images import resized_img_src.

Configuration

Configure Flask-Images via the following keys in the Flask config:

• IMAGES_URL: The url to mount Flask-Images to; defaults to ‘/imgsizer’.

• IMAGES_NAME: The name of the registered endpoint used in url_for.

• IMAGES_PATH: A list of paths to search for images (relative to app.root_path); e.g. [‘static/uploads’]

• IMAGES_CACHE: Where to store resized images; defaults to ‘/tmp/flask-images’.

• IMAGES_MAX_AGE: How long to tell the browser to cache missing results; defaults to 3600. Usually, we will set a max age of one year, and cache bust via the modification time of the source image.