The window cards came in one of three sizes with 14" x 22" tending to be the standard. There was also a jumbo 22" x 28" and a miniature 8" x 14" . Across the top of the two smaller sizes was usually a blank border where theater owners would write information about dates and showtimes. Info via Learn About Movie Posters.
All three sizes were employed with the RKO general release of Snow White.
- Regular (original cost to theatre owners was 7¢). Copyrighted 1938.
Image via Heritage Auctions.
- Jumbo (10¢).
Image courtesy of Rick Payne via dadric's attic.
- Miniature (4¢). Not yet located.
In addition, there was also a hard-to-find, first edition red-style "regular" size window card dated from 1937. Unlike the blue version pictured above, this one had an orangish background.