I note here the code for importing an image as a watermark - https://kb.aspose.com/slides/python/how-to-add-image-watermark-in-pptx-using-python/
Is it possible to adjust the transparency of the imported image?
@bowespublishing,
Thank you for posting your question.
With Aspose.Slides for Python, you can add transparency for an image in a PowerPoint document as shown below:
# The picture_frame variable is an instance of the PictureFrame class here.
picture_frame.picture_format.picture.image_transform.add_alpha_modulate_fixed_effect(50)
API Reference: ImageTransformOperationCollection class