For this task we may create validate_image function and add it to validators attribute of ImageField.
# file models.py
from django.core.exceptions import ValidationError
def validate_image(image):
file_size = image.file.size
limit_kb = 150
if file_size > limit_kb * 1024:
raise ValidationError("Max size of file is %s KB" % limit)
#limit_mb = 8
#if file_size > limit_mb * 1024 * 1024:
# raise ValidationError("Max size of file is %s MB" % limit_mb)
class Photo(models.Model):
image = models.ImageField('Image', upload_to=image_upload_path, validators=[validate_image])