Use ImageOutput.geterror.

Author: KelSolaar

colour/io/image.py

@@ -698,6 +698,9 @@ def write_image_OpenImageIO(
 
     image_output = ImageOutput.create(path)
 
+    if not image_output:
+        print(image_output.geterror())
+
     image_output.open(path, image_specification)
     success = image_output.write_image(image)