Generate thumbnails for any part images existing in the database

InvenTree/part/migrations/0034_auto_20200404_1238.py

@@ -0,0 +1,28 @@
+# Generated by Django 2.2.10 on 2020-04-04 12:38
+
+from django.db import migrations
+
+from part.models import Part
+from stdimage.utils import render_variations
+
+
+def create_thumbnails(apps, schema_editor):
+    """
+    Create thumbnails for all existing Part images.
+    """
+
+    for part in Part.objects.all():
+        # Render thumbnail for each existing Part 
+        if part.image:
+            part.image.render_variations()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0033_auto_20200404_0445'),
+    ]
+
+    operations = [
+        migrations.RunPython(create_thumbnails),
+    ]