If you add a few products with photos, and then look at the product administration list in the browser, it will look similar to the following screenshot:

The list_display property is usually used to define the fields to display in the administration list view; for example, title and price are fields of the Product model. Besides the normal field names, though, the list_display property also accepts the following:

• A function, or another callable
• The name of an attribute of the admin model
• The name of an attribute of the model

When using callables in list_display, each one will get the model instance passed as the first argument. Therefore, in our example, we have defined the get_photo() method in the model admin class, and that receives the Product instance as obj. The method tries to get the first ProductPhoto object from the many-to-one relationship, and, if it exists, it returns HTML generated from the include template, with the <img> tag linked to the detail page for  Product.

You can set several attributes for the callables that you use in list_display. The short_description attribute of the callable defines the title shown at the top of the column, for instance. When content will not sort naturally, the admin_order_field attribute can be set to another field name, optionally using a hyphen prefix to indicate a reversed sort order.

Finally, the Price field is made editable by including it in the list_editable setting, and, as there are editable fields, a Save button is introduced at the bottom, to save the whole list of products.