Django model dependent image size validation

Django model dependent image size validation

# Model dependent image size validation

# forms.py
from django import forms
from .models import *
from django.core.files.images import get_image_dimensions


class ValidateImageForm(forms.ModelForm):
   class Meta:
       model = MyModel # Model name
       field = "image" # Field name
       MinW = 1280 # Min. Width
       MaxW = 1500 # Max. Width
       checkH = False # If it's going to validate the height
       MinH = 400 # Min. Height
       MaxH = 1000 # Max. Height
       text_minw = u"The image width is lower than %i" % MinW # Error text for min. width
       text_maxw = u"The image width is larger than %i" % MaxW # Error text for max. width
       text_minh = u"The image height is lower than %i" % MinH # Error text for min. height
       text_maxh = u"The image height is larger than %i" % MaxH # Error text for max. height

    #clean_(name of field)
   def clean_image(self):
       image = self.cleaned_data.get(self.Meta.field)
       if not image:
           raise forms.ValidationError(u"No image")
       else:
           w, h = get_image_dimensions(image)
           if w < self.Meta.MinW:
               raise forms.ValidationError(self.Meta.text_minw)
           if w > self.Meta.MaxW:
               raise forms.ValidationError(self.Meta.texo_maxw)
           if h < self.Meta.MinH and self.Meta.checkH == True:
               raise forms.ValidationError(self.Meta.text_minw)
           if h > self.Meta.MaxH and self.Meta.checkH == True:
               raise forms.ValidationError(self.Meta.text_maxw)

       return image
       
# Inheritance 

class ValidateDemoForm(ValidateImageForm):
    class Meta(ValidateImageForm.Meta):
        model = Demo
        MaxW = 1900
        MinW = 1280
        text_minw = u"The image width is lower than %i" % MinW
        text_maxw = u"The image width is larger than %i" % MaxW

# If the model has a thumbnail too.
class ValidateDemoForm(ValidateImageForm):
    class Meta(ValidateImageForm.Meta):
        model = Demo
        MaxW = 1900
        MinW = 1280
        text_minw = u"The image width is lower than %i" % MinW
        text_maxw = u"The image width is larger than %i" % MaxW
    
    #Validate the thumbnail field
    def clean_thumb(self):
       thumb = self.cleaned_data.get("thumb")
       if not thumb:
           raise forms.ValidationError(u"No image")
       else:
           w, h = get_image_dimensions(thumb)
           if w < 300:
               raise forms.ValidationError(u"The image width is lower than 300px")
           if w > 300:
               raise forms.ValidationError(u"The image width is larger than 300px")
           if h < 197:
               raise forms.ValidationError(u"The image height is lower than 197px")
           if h > 197:
               raise forms.ValidationError(u"The image height is larger than 197px")

       return thumb

thanks