Do you know if by making the images "Public" in IBM Cloud Object Storage it really becomes public meaning you can find the resources through web browser as google? or it becomes like "shared via link" because IBM COS provides a link, and that works just fine for the Watson Assistant image responses, but are those images unsafe somehow?
When making a folder in S3 / IBM Cloud Object Storage (COS) PUBLIC, the content is accessible. Because there are tools (and attackers) that scan for host names, IP addresses and available services, there is a chance that a scanner might find the offered resources (images). Public is public.
I have used images stored on COS in a public folder for chatbots developed with IBM Watson Assistant in image responses. If you use the web chat feature and users access the chatbot, they could download the images - the images are "public".