Basic

The smallest complete setup: one alias, one model field, one serializer field, and a viewset that returns a single thumbnail URL.

1. Define a thumbnail alias

In settings.py, register a non-targeted avatar alias under the empty-string key so any image field can use it:

INSTALLED_APPS = [
    # ...
    'easy_thumbnails',
    'rest_framework',
]

THUMBNAIL_ALIASES = {
    '': {
        'avatar': {'size': (50, 50), 'crop': True},
    },
}

2. Use ThumbnailerImageField on your model

Use easy-thumbnails’ ThumbnailerImageField so the field knows how to produce thumbnails:

from django.db import models
from easy_thumbnails.fields import ThumbnailerImageField


class Profile(models.Model):
    name = models.CharField(max_length=100)
    image = ThumbnailerImageField(upload_to='photos')

3. Add the serializer field

Point ThumbnailerSerializer at the avatar alias name:

from rest_framework import serializers
from easy_thumbnails_rest.serializers import ThumbnailerSerializer

from .models import Profile


class ProfileSerializer(serializers.ModelSerializer):
    image = ThumbnailerSerializer(alias='avatar')

    class Meta:
        model = Profile
        fields = ['id', 'name', 'image']

4. Serve it from a viewset

A standard DRF viewset is all you need — it passes the request into serializer context automatically, so the field can build absolute URLs:

from rest_framework import viewsets

from .models import Profile
from .serializers import ProfileSerializer


class ProfileViewSet(viewsets.ModelViewSet):
    queryset = Profile.objects.all()
    serializer_class = ProfileSerializer

5. The response

A GET on a profile returns the avatar thumbnail as a single absolute URL:

{
  "id": 1,
  "name": "Ada Lovelace",
  "image": "http://example.com/media/photos/example.jpg.50x50_q85_crop.jpg"
}

Next steps

List & JSON example — return every size under a target as a list and as a keyed map.
Configuration — alias options and the difference between alias names and target keys.