diff --git a/helpers/images.py b/helpers/images.py
index 837c5009..c229dd14 100644
--- a/helpers/images.py
+++ b/helpers/images.py
@@ -25,11 +25,11 @@ def image_as_base64(image_file):
     #    encoded_string = base64.b64encode(img_f.read())
     encoded_string = base64.b64encode(image_file.file.read())
     mimetype, enc = mimetypes.guess_type(image_file.path)
+    # Treat unknown files as dicom
+    if None == mimetype:
+        return "data:application/dicom;base64,{}".format(encoded_string.decode("utf-8"))
     if "dicom" in mimetype or "octet-stream" in mimetype:
         return "data:{};base64,{}".format(mimetype, encoded_string.decode("utf-8"))
-    # Treat unknown files as dicom
-    if None in mimetype:
-        return "data:application/dicom;base64,{}".format(encoded_string.decode("utf-8"))
     return "data:image/{};base64,{}".format(mimetype, encoded_string.decode("utf-8"))