Portraits of the interiors of places from when having a portrait made of the rooms in your home was in. What they’d photograph now. These by Danish artist Josef Theodor Hansen (1848-1912).

"Gustaf III:s sengkammer Drottnigholms slott." Signed and dated 1887. Oil on canvas.
“Gustaf III:s sengkammer Drottnigholms slott.” Signed and dated 1887. Oil on canvas. Image © 2008-2020 Bukowski Auktioner AB. Fair use license. via https://www.bukowskis.com/en/lots/884658-josef-theodor-hansen-oil-on-canvas-signed-and-dated-1887
"Kirkeinteriør fra domkirken i Monreale, Sicilien." 1906.
“Kirkeinteriør fra domkirken i Monreale, Sicilien.” 1906. Image source Bruun Rasmussen Auctions. In the public domain in the United States because the artist has been dead over 70 years. via https://commons.wikimedia.org/wiki/File:Josef_Theodor_Hansen_-_Kirkeinteri%C3%B8r_fra_domkirken_i_Monreale,_Sicilien_-_1906.png
"The Sala delle Quattro Porte, Doge's Palace, Venice."
“The Sala delle Quattro Porte, Doge’s Palace, Venice.” Signed and dated “J. T. Hansen./Venezia 1905-06” on the lower right. Oil on canvas. Image © CHRISTIE’S 2020. Fair use license. via https://www.christies.com/lotfinder/Lot/josef-theodor-hansen-danish-1848-1912-the-sala-6165791-details.aspx
"Pompejiansk interiør." No date.
“Pompejiansk interiør.” No date. In the public domain due to age. via http://viticodevagamundo.blogspot.com/2019/07/pompeii-bt-josef-theodor-hansen.html

Watercolors of Windsor Castle and other royal residences back before Victoria and Albert lived there by English watercolorist Charles Wild. Living from 1781 to 1835, he specialized in painting architecture and exhibited at the Royal Academy.

Frogmore_House,_Green_Pavilion,_by_Charles_Wild,_1817_-_royal_coll_922121_257043_ORI_0_0
“Green Pavilion, Frogmore House.” 1817. Watercolor with touches of bodycolor over pencil with an engraved aquatint version published as plate 29 of W.H. Pyne’s 1819 work “The History of the Royal Residences.” Royal Collection Trust. In the public domain in the United States because the artist died over 70 years ago. via https://commons.wikimedia.org/wiki/File:Frogmore_House,_Green_Pavilion,_by_Charles_Wild,_1817_-_royal_coll_922121_257043_ORI_0_0.jpg
"Queen's Presence Chamber, Windsor Castle." 1817.
“Queen’s Presence Chamber, Windsor Castle.” 1817. English. Watercolor with touches of bodycolor over pencil with an engraved aquatint version published as plate 7 of W.H. Pyne’s 1819 work “The History of the Royal Residences.” Royal Collection Trust. In the public domain in the United States because the artist died over 70 years ago. via https://commons.wikimedia.org/wiki/File:Windsor_Castle,_Queen%27s_Presence_Chamber,_by_Charles_Wild,_1817_-_royal_coll_922099_257019_ORI_0.jpg
Hampton_Court_Palace,_Chapel,_by_Charles_Wild,_1819_-_royal_coll_922125_313698_ORI_2
“Chapel, Hampton Court Palace.” 1819. Watercolor with touches of bodycolor over pencil with an engraved aquatint version published as plate 33 of W.H. Pyne’s 1819 work “The History of the Royal Residences.” Royal Collection Trust. In the public domain in the United States because the artist died over 70 years ago. via https://commons.wikimedia.org/wiki/File:Hampton_Court_Palace,_Chapel,_by_Charles_Wild,_1819_-_royal_coll_922125_313698_ORI_2.jpg
Carlton_House,_Throne_Room,_by_Charles_Wild,_1818_-_royal_coll_922178_257094_ORI_0_0
“Throne Room, Carlton House.” ca. 1818. Watercolour with touches of bodycolour and gum arabic over pencil with an engraved aquatint version published as plate 86 of W.H. Pyne’s 1819 work “The History of the Royal Residences.” Royal Collection Trust. In the public domain in the United States because the artist died over 70 years ago. via https://commons.wikimedia.org/wiki/File:Carlton_House,_Throne_Room,_by_Charles_Wild,_1818_-_royal_coll_922178_257094_ORI_0_0.jpg
Screenshot (107)
“The King’s Closet, Windsor Castle.” Aquatint engraving, taken from W.H. Pyne’s 1819 work “The History of the Royal Residences.” William James Bennett,, engraver, after Charles Wild. In the public domain due to age. via https://fineartamerica.com/featured/the-kings-closet-windsor-castle-charles-wild.html
"The Ante Chamber to the Throne Room, Carlton House." ca. 1816.
“The Ante Chamber to the Throne Room, Carlton House.” ca. 1816. Watercolour, bodycolour and gum arabic over etched lines. Royal Collection Trust. In the public domain in the United States because the artist died over 70 years ago. via https://www.rct.uk/collection/922179/the-ante-chamber-to-the-throne-room-carlton-house

Pictures of a never-realized interior renovation of the Royal Serbian Castle in Belgrade. World War I came along and so they never happened. Taken from two albums, “Drafts for the royal Hofburg of His Majesty King Peter of Serbia. Belgrade” done between 1912 and 1914 by August Bosse,who owned a major interior design firm in Weimar. These being a selection from the website of Antiquariat Michael Banzhaf who I met at Boston’s antiquarian book fair last fall.

Hall with columns.
Hall with columns. Image © Michael Banzhaf, Tübingen antiquariat-banzhaf.de. Fair use license. via http://www.antiquariat-banzhaf.de/wp-content/uploads/Banzhaf-Katalog-16.pdf
Sitting room.
Sitting room. Image © Michael Banzhaf, Tübingen antiquariat-banzhaf.de. Fair use license. via http://www.antiquariat-banzhaf.de/wp-content/uploads/Banzhaf-Katalog-16.pdf
Room with domed ceiling.
Room with domed ceiling. Image © Michael Banzhaf, Tübingen antiquariat-banzhaf.de. Fair use license. via http://www.antiquariat-banzhaf.de/wp-content/uploads/Banzhaf-Katalog-16.pdf
Screenshot (99)
Room with yellow wallpaper. Image © Michael Banzhaf, Tübingen antiquariat-banzhaf.de. Fair use license. via http://www.antiquariat-banzhaf.de/wp-content/uploads/Banzhaf-Katalog-16.pdf
Room with blue wallpaper.
Room with blue wallpaper. Image © Michael Banzhaf, Tübingen antiquariat-banzhaf.de. Fair use license. via http://www.antiquariat-banzhaf.de/wp-content/uploads/Banzhaf-Katalog-16.pdf
Room with red carpet.
Room with red carpet. Image © Michael Banzhaf, Tübingen antiquariat-banzhaf.de. Fair use license. via http://www.antiquariat-banzhaf.de/wp-content/uploads/Banzhaf-Katalog-16.pdf

I apologize for the quality of the last  3 which is not as good as I would like. The images are taken via screenshots from a PDF from antiquariat-banzhaf.de and the last 3 are small on the PDF. Great albums, I can find no images of it elsewhere to use.

Room interiors so detailed you could walk right in and sit down. American. Walter Gay, artist (1856-1937). A friend of John Singer Sargent with whom he studied under Léon Bonnat.

"The Fragonard Room at the Frick Collection." 1926.
“The Fragonard Room at the Frick Collection.” 1926. Collection of the Frick, Pittsburgh. In the public domain due to age. via https://artsandculture.google.com/asset/the-fragonard-room/2wEAUIeWAaAFeQ
"Galerie des Bustes, Château du Reveillon." 1907-1909.
“Galerie des Bustes, Château du Reveillon.” 1907-1909. Oil on canvas. In the public domain in the United States because the artist died over 70 years ago. via https://commons.wikimedia.org/wiki/File:Walter_Gay_-_Galerie_des_Bustes,_Chaeau_du_Reveillon.jpg
Les-Tableaux-Le-Breau-Walter-Gay-oil-painting-768x629
“Les Tableaux Le Breau.” ca. 1918. Collection of the Dumbarton Oaks Research Library and Collection. In the public domain in the United States because the artist has been dead over 70 years. via https://www.oceansbridge.com/shop/artists/g/ga-gaz/gay-walter/les-tableaux-le-breau

Watercolors of rooms in the Doge’s Palace in Venice with lots of people wandering around. Italian. Giovanni Battista della Libera, artist (1826-1886).

"La salle de Grand Council." ca. 1850.
“La salle de Grand Council.” ca. 1850. © 1stdibs, Inc. 2019. Fair use license. via https://www.1stdibs.com/furniture/wall-decorations/paintings/giovanni-battista-della-libera-rare-set-of-six-watercolor-views-doges-palace/id-f_16692871/
"Antichambre de la salle du collège." ca. 1850.
“Antichambre de la salle du collège.” ca. 1850. Image © 1stdibs, Inc. 2019. Fair use license. via https://www.1stdibs.com/furniture/wall-decorations/paintings/giovanni-battista-della-libera-rare-set-of-six-watercolor-views-doges-palace/id-f_16692871/
"La salle du collège." ca. 1850.
“La salle du collège.” ca. 1850. Image © 1stdibs, Inc. 2019. Fair use license. via https://www.1stdibs.com/furniture/wall-decorations/paintings/giovanni-battista-della-libera-rare-set-of-six-watercolor-views-doges-palace/id-f_16692871/

Interiors in glorious detail, painted by Russian Parisian Alexander Serebryakov who was also a decorator. Must be why the details are so well done. Lived from 1907 to 1995. Grand nephew of Alexandre Benois who did much design work for the Ballets Russes.

"Interior of Serge Ivanoff’s studio in Paris." 1944.
“Interior of Serge Ivanoff’s studio in Paris.” 1944. © Estate of the artist. Image © 2019 MCH Group | Curiator. Fair use license. via https://curiator.com/art/alexandre-serebriakoff/interior-of-the-studio-serge-ivanov-in-paris
"Small Dining Room, Château de Sainte Mesme." 1983.
“Small Dining Room, Château de Sainte Mesme.” 1983.© Estate of the artist. Image © 2019 MCH Group | Curiator. Fair use license. via https://curiator.com/art/alexandre-serebriakoff/small-dining-room-chateau-de-ste-mesme
"The Dining Room, Château de Sainte Mesme." No date.
“The Dining Room, Château de Sainte Mesme.” No date. © Estate of the artist. Image © 2019 MCH Group | Curiator. Fair use license. via https://curiator.com/art/alexandre-serebriakoff/the-dining-room-chateau-de-ste-mesme
"Red Room of the Castle of Saint-Meme." 1981.
“Red Room of the Castle of Saint-Meme.” 1981. © Estate of the artist. Image © 2019 MCH Group | Curiator. Fair use license. via https://curiator.com/art/alexandre-serebriakoff/le-salon-rouge-du-chateau-de-sainte-mesme-red-room-of-the-castle-of-sa

Paintings of rooms at Versailles with furniture and sculptures but with the people mysteriously absent. French. Maurice Lobre, artist (1862-1951). Intimist style.

Chateau de Versailles, said to be Marie Antoinette's study. 1895.
Chateau de Versailles, said to be Marie Antoinette’s study. 1895. Oil on canvas. © Estate of the artist. Image © 2019 MutualArt Services, Inc. Fair use license. via https://www.mutualart.com/Artwork/French-interior–said-to-be-marie-antoin/A9F4161D0308E677
"De Salon du Dauphin in Versailles." 1901.
“De Salon du Dauphin in Versailles.” 1901. © Estate of the artist.Image © 2019 MCH Group | Curiator. Fair use license. via https://curiator.com/art/maurice-lobre/de-salon-du-dauphin-in-versailles
Bibliothèque du dauphin -Lobre- Библиотека дофин
Library of the Dauphin at Versailles. 1903. © Estate of the artist. Collection of the Lviv National Museum, Ukraine. Fair use license. via http://www.collectionchtchoukine.com/artistes/maurice-lobre#jp-carousel-2012