English: Circa 1907–08. This particular copy of the postcard was postmarked on February 28, 1908. Other copies have been postmarked in 1907 and 1908.

English: Scanned by Cardcow as postcard #132877 in their database. The postcard was postmarked in Whitehall, Montana and addressed to Payette, Idaho. The image was digitally retouched to remove a Cardcow watermark.

English: Anonymous. Neither the illustrator nor the publisher/printer are identified on any currently known copies of the postcard, nor have they been identified by secondary sources.

No artist's signature appears on the illustration itself (or on other postcards in the same series). The liner notes for In the Aeroplane Over the Sea contain the credit "Art Direction: Chris Bilheimer & Jeff Mangum", without describing (much less attributing) the postcard used to create the cover design. On page 81 of Kim Cooper's 2005 book about In the Aeroplane Over the Sea (#29 in the 33⅓ series, ISBN 0-8264-1690-X), it is described simply as "a vintage European postcard of bathers at a resort" purchased by Mangum from a thrift shop, with no indication of authorship.