Improvements for Image Branding

[Jailander]

In strands-project/strands_utils#112 some improvements were suggested by @cburbridge for this module, just reposting the suggestion here to close the issue on the strands_utils repository

"Sounds good. At the moment the code adds the rgb of the overlay to the RGB of the image:
output_image = input_image + 0.7 overlay. I was thinking maybe add an option to use the transparency channel of the PNG to allow overlaying as a replacement:
output_image = input_image if overlay is transparent else overlay
This way, it would be possible to overlay something on top of white backgrounds, and colours wont be diluted by the background.

Would it be better as a service rather than action? We could also add an option to process image streams continuously."