Can you find the images yourself 'through' the symlink. E.g. does ls public/storage/ list the content of storage/app/public? Then try ls public/storage/trainee-profile-pictures etc. If not, then the sy

Something to try is make your own symlink instead of relying on artisan: sudo ln -snf /home/customer/www/<path>/storage/app/public /home/customer/www/<path>/public/storage

If that all works, then I'd guess it's a problem with reading the files. Seems like you already checked permissions, so maybe try dumping the images into the actual public folder directly, instead of using the symlink (just delete it), and see if the code finds the files then.

Is there any error message logged when failing to read the images?

Thanks for making your question so easy to read