I just went down a vintage rabbit hole, something I love when it happens! I was getting ready to list a favorite jacket at MagsRags.net - it's up now, and photo is clickable.
And then I scrolled back up to the opening post of this thread. Omigod, it's the same jacket! I used tineye.com to see if I could figure out where the image was posted first online, and found the full double page spread version at JeanPatchett.com
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That's Suzy Parker in my jacket, Jean Patchett next to her, and Dovima on the far right. The ad is from Vogue magazine, January 1953. The only tag in my jacket is from Wm H Block, a high end department store in Indianapolis. But thanks to the ad, I now know that the jacket was made by Swansdown, a company I had never heard of. After seeing some other Swansdown jackets, suits, and coats online, I am even more impressed. Lilli Ann levels of design, IMO.
One other tidbit about Jean Patchett - I never knew that
@Alleycats avatar is a Jean Patchett photo!