Only way I know of to automate this would be to use the API’s or you could also try and see if CSS updates could that for you by realign the default picture; you would need to have the image in a place were it can be loaded, like your own servers or you could try loading it under the S3 bucket of image assets (Docebo tool you can upload images to - you can see it with exams or surveys then use the URL).
Great idea for a new Idea!!!
Indeed...for all assets, e-learning, ILT, LP...like they've done for new course player header options.