django-mediacat - The best way to store pictures of cats

Mediacat is an opinionated Media Library for Django, lovingly extracted from the codebase of onefinestay.

It's not quite ready yet, but here's a screenshot of the current state of play:

Data Model

Mediacat is built around around two major models, Images and Crops. An Image represents an original uploaded file, along with some metadata, and a Crop represents a rectangular subsection of a specific image. Crops are also constrained to being one of a number of developer-defined ratios.

A crop can be attached to the model through the use of a MediaField. A MediaField looks like a regular Django model field, with some extra magic that happens in the background:

from django.db import models
from mediacat.fields import MediaField

class Foo(models.Model):
    ...
    field_name = MediaField('PORTRAIT', width=2000)

Rather than using a foreign key as a column in the parent model's database, Mediacat instead has an ImageCropApplication model which stores the relationship instead. The reasoning behind this unconventional apporach is to simplify the database joins required to render a list of Django models that may have multiple MediaFields.

Mediacat also provides the facade of a category structure, in reality the categories are defined as a hierarchy of your application's models, and images are associated with the models via an intermediate ImageAssocation model. This is the second unconventional design decision, made because it let us avoid the problem of having to keep a hierarchy of categories in sync with our business models.