• Costumes •
Clothes that you only wear occasionally for a specific purpose. This excludes apparel that is MADE for a specific purpose like a bathing suit is made for swimming. To me, this isn't the same category as a costume worn for a specific event like a wedding, The Preakness, a performance and/or a holiday like Halloween.
• Uniforms •
This is a specific group for clothing people are wearing doing or representing their profession. This includes common apparel if all the employees are wearing the same outfit and it is shown in the image.
HMS Magpie was a modified Black Swan Class sloop. This image shows Prince Phillip embarking at Malta in 1952. He took command in 1950. After Magpie, he had other Royal duties which prevented him from a sea command again