(modeladmin_custom_clean)= # Adding a custom clean method to your ModelAdmin models The simplest way is to extend your ModelAdmin model and add a clean() model to it. For example: ```python from django import forms from django.db import models class ModelAdminModel(models.Model): def clean(self): if self.image.width < 1920 or self.image.height < 1080: raise forms.ValidationError("The image must be at least 1920x1080 pixels in size.") ``` This will run the clean and raise the `ValidationError` whenever you save the model and the check fails. The error will be displayed at the top of the wagtail admin. If you want more fine grained-control you can add a custom `clean()` method to the `WagtailAdminPageForm` of your model. You can override the form of your ModelAdmin in a similar matter as wagtail Pages. So, create a custom `WagtailAdminPageForm`: ```python from wagtail.admin.forms import WagtailAdminPageForm class ModelAdminModelForm(WagtailAdminPageForm): def clean(self): cleaned_data = super().clean() image = cleaned_data.get("image") if image and image.width < 1920 or image.height < 1080: self.add_error("image", "The image must be at least 1920x1080px") return cleaned_data ``` And then set the `base_form_class` of your model: ```python from django.db import models class ModelAdminModel(models.Model): base_form_class = ModelAdminModelForm ``` Using `self.add_error` will display the error to the particular field that has the error.