further improvements

longs/migrations/0008_alter_longseriesimage_series.py

@@ -0,0 +1,19 @@
+# Generated by Django 4.1.4 on 2023-08-14 12:31
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('longs', '0007_longseriesimage_image_md5_hash_and_more'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='longseriesimage',
+            name='series',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.CASCADE, related_name='images', to='longs.longseries'),
+        ),
+    ]

longs/models.py

@@ -354,7 +354,7 @@ def test_image_validator(file):
 class LongSeriesImage(SeriesImageBase):
     image = models.FileField(upload_to=image_directory_path)
     series = models.ForeignKey(
-        "LongSeries", related_name="images", on_delete=models.SET_NULL, null=True
+        "LongSeries", related_name="images", on_delete=models.CASCADE, null=True
     )