diff --git a/src/documents/management/commands/document_thumbnails.py b/src/documents/management/commands/document_thumbnails.py
index c9928c7cc..595d8ba3b 100644
--- a/src/documents/management/commands/document_thumbnails.py
+++ b/src/documents/management/commands/document_thumbnails.py
@@ -1,6 +1,7 @@
 import logging
 import multiprocessing
 import shutil
+from pathlib import Path
 
 import tqdm
 from django import db
@@ -11,7 +12,7 @@ from ...parsers import get_parser_class_for_mime_type
 
 
 def _process_document(doc_in):
-    document = Document.objects.get(id=doc_in)
+    document: Document = Document.objects.get(id=doc_in)
     parser_class = get_parser_class_for_mime_type(document.mime_type)
 
     if parser_class:
@@ -21,6 +22,13 @@ def _process_document(doc_in):
         return
 
     try:
+
+        existing_thumbnail = Path(document.thumbnail_path).resolve()
+
+        # Remove an existing PNG format thumbnail, if it existed
+        if existing_thumbnail.exists() and existing_thumbnail.suffix == ".png":
+            existing_thumbnail.unlink()
+
         thumb = parser.get_optimised_thumbnail(
             document.source_path,
             document.mime_type,
@@ -69,7 +77,7 @@ class Command(BaseCommand):
         ids = [doc.id for doc in documents]
 
         # Note to future self: this prevents django from reusing database
-        # conncetions between processes, which is bad and does not work
+        # connections between processes, which is bad and does not work
         # with postgres.
         db.connections.close_all()