Variable lists, also known as a many-to-one relationship, are usually handled by making a separate model for the many and, in that model, using a ForeignKey to the "one".
There isn't an app like this in django.contrib, but there are several external projects you can use, e.g. django-photologue which even has some support for viewing the images in the admin.
The admin site can't be made "user proof", it should only be used by trusted users. Given this, the way to make your admin site decent would be to define a ModelAdmin for your property and then inline the photos (inline documentation).
So, to give you some quick drafts, everything would look something like this:
# models.py
class Property(models.Model):
address = models.TextField()
...
class PropertyImage(models.Model):
property = models.ForeignKey(Property, related_name='images')
image = models.ImageField()
and:
# admin.py
class PropertyImageInline(admin.TabularInline):
model = PropertyImage
extra = 3
class PropertyAdmin(admin.ModelAdmin):
inlines = [ PropertyImageInline, ]
admin.site.register(Property, PropertyAdmin)
The reason for using the related_name argument on the ForeignKey is so your queries will be more readable, e.g. in this case you can do something like this in your view:
property = Property.objects.get(pk=1)
image_list = property.images.all()
EDIT: forgot to mention, you can then implement drag-and-drop ordering in the admin using Simon Willison's snippet Orderable inlines using drag and drop with jQuery UI
