20,000 hi-res British historical artworks in the public domain, newly online from the Yale Center for British Art. My test downloads freely yeiled up hi-res .TIF files, with only a simple numerical “captcha” to fill before each download.
Size seems to be 3000px at 300dpi, around 18Mb to 20Mb, which is suitable for a magazine double-page spread. There are often lengthy curatorial commentaries, though these are presumably not in the public domain.
Re-finding seems impossible, with the numbers embedded in each file name being unknown to either Google or the Yale Center for British Art website search, so one would do well to save a PDF of each picture’s page along with its hi-res file. Or the simple .txt of the caption, which excludes the curatorial commentary, though the picture’s given title is not always clearly indicated in this.
“The French Lady in London”, c. 1771. French hairdressers residing in London “were often singled out for particular opprobrium”, and their extraordinarily elaborate creations in women’s hairstyles were the subject of caricature in the press.