Django rest framework errors in trying to persist an image

This is my UserProfile object,

class UserProfile(models.Model):
    user = models.OneToOneField(User, related_name='profile', on_delete=models.CASCADE, )
    badge = models.ImageField(upload_to='media/badges/', null=True)
    reputation = models.IntegerField(default=0)
    status = models.CharField(max_length=255, null=True, blank=True)
    thumbnail = models.ImageField(upload_to='media/user/', blank=True, null=True)

This is the Serializer,

class UserProfileSerializer(serializers.ModelSerializer):
    thumbnail = serializers.ImageField(max_length=None, use_url=True, read_only=True)

    class Meta:
        model = models.UserProfile
        fields = ('badge', 'reputation', 'status', 'thumbnail',)

This the api that tries to save the image,

class CreateUpdateUserThumbnail(views.APIView):

    def post(self, request, **kwargs):
        user = User.objects.get(id=kwargs.get('user_id'))
        user.profile.thumbnail = UserProfileSerializer(instance=user.profile, data=request.data)
        if user.profile.thumbnail.is_valid():
            user.profile.thumbnail.save()
            return Response(user.profile.thumbnail.data, status=status.HTTP_201_CREATED)
        else:
            return Response(user.profile.thumbnail.errors, status=status.HTTP_400_BAD_REQUEST)

When I try to upload an image to this endpoint this is the error that I get,

AttributeError: 'UserProfileSerializer' object has no attribute '_committed'

What am I doing wrong here?