Image and price display with placehold.it in django admin

admin.py

class ClothAdmin(admin.ModelAdmin):
    list_display = ('name', 'category', 'description', 'price_display', 'image_display',)
    search_fields = ('name', 'category', 'description', 'price',)
    list_filter = ('category',)

    def price_display(self, obj):
        return '${:20,d}'.format(obj.price)
        
    price_display.short_description = 'precio'
    price_display.admin_order_field = 'price'

    def image_display(self, obj):
        if obj.image:
            return '<img src="%s" width="60px" height="60px">' % (obj.image.url)
        else:
            return '<img src="%s" width="60px" height="60px">' % ('http://placehold.it/60x60')

    image_display.allow_tags = True
    image_display.admin_order_field = 'imagen'
    image_display.short_description = 'Imagen'