Images
餓鬼草紙2(東京国立博物館本2) by 日本の美術
Translated, the title roughly means "Gaki Soushi (a picture scroll about gaki) 2 (From the Tokyo National Museum 2)" by "Art of Japan." The site contains many images of Japanese art, but this particular URL leads you to a small collection of paintings of gaki.
福井 神明神社 神明かり by teamLab
This is an art installation of "floating, resonating spheres" exhibited at a shrine to Amaterasu in Fukui Prefecture in Japan.
Ubume, the Yōkai Who Was Once Human by Dr. Yokai
An article on ubume, with some pretty graphic images (har-har) attached. A very nice visual aid to learn about the tragic spirit.
Ubume by Wikipedia JP
More images of ubume! Along with an article, but as it's in Japanese, it isn't much good if you can't read it. Nonetheless, great images.
杉山ニット工業『ざしきわらし金運袋』 by Binchoutan
An online store with various organic commodities, this particular item is a sack for economic fortune embroidered with an image of a zashiki-warashi, made by Sugiyama Knit Ind.
日本妖怪海軍vs中華漁船 by Guts & Yo!
A blog about youkai news, it also doubles as a fine source for images of some funayurei.
日曜洋画劇場「HOME 愛しの座敷わらし」 by Teleneko
This blog is about dramas and other TV programs, but this particular article is about the film "Home: Itoshi no Zashiki Warashi," or "Home: The Beloved Zashiki Warashi." An alternate English title, "Home: The House Imp" is also extant. One can imagine why I would suggest this article, but beyond the interesting analysis, it also offers screencaps.
座敷童子 by Wikipedia JP
More info on zashiki warashi, and more images, to boot!
三匹の陽気なおばけ の無料イラスト by illustrain
A cute image of three ghosts. The title reads "Three Happy Ghosts: Free Illustration."
しりょう、いきりょう by atelier CROMAGNON
A humorous illustration of a shiryou (ghost) and ikiryou.
Yokai.com by Matthew Meyer
Meyer is a prolific artist of youkai, illustrating a series called "A-Yokai-A-Day" and even a book. On this site, Meyer not only explains in detail about youkai, but provides enigmatic and lively pictures to go with them. Truly a great reference for learning about youkai.
Japanese Art by Peabody Essex Museum
A tidy online collection of Japanese art across various mediums. While not strictly youkai or obake-related, it's a great image resource to have anyhow if interested in Japanese art.
Wikia: Ju-On by Wikia
Wikia, Wikipedia's lesser-known and more community-based sister, is slightly less reliable for information. However, it is great for images!
Oni by Wikipedia
A Wikipedia article on oni, which is pretty fascinating. Otherwise, the images are a great resource as well.
Horror Archives by Tofugu (various)
An archive of posts about horror on Tofugu. An interesting read with plentiful pictures.
Classic Japanese Wave Pattern by PatternCooler
Great for background image creation.
Tokyo Night View by EiGHT Air Photography
A small gallery of images taken from a helicopter, all featuring the Tokyo cityscape at night.
A-Yokai-A-Day by Matthew Meyer
Previously mentioned though Meyer may be, this archive of images he has created are a fun thing to peruse if interested.
Aokigahara: Japan’s Macabre ‘Suicide Forest’, “The Perfect Place to Die” by R.E. Hadlock
A morbid article about Aokigahara, Japan's suicide forest. It's quite gruesome, so please proceed with caution. The imagery of the forest is awe-inspiring as much as it is chilling.
Utagawa Toyokuni's "Onoe Matsusake as the Ghost of the Murdered Wife Oiwa" by Toyokuni, hosted by the Metropolitan Museum of Art
A painting of Oiwa, a pivotal character in the kaidan "Yotsuya Kaidan." The painting illustrates Onoe Matsusuke, an actor, playing the role of Oiwa, who returns as an onryo.
tea, coffee, and books by Taylor Cole
An image of a hot beverage and books.
FreeDesigner by FreeDesigner
A nice array of free images for designers.
Suzzalo Library by Wonderlane
An image of Suzzalo Library.
Google's Best Perk: The Library in Building 42 by Tomasz Tunguz
An image of the Library in Building 42, on Google's campus. Pretty neat.
Subtle Patterns by Atle Mo
A fantastic assortment of subtle patterns. Great design sense, too.