[1] [CITE@en[Google Photos APIs  |  Google Developers]]
([TIME[2018-05-09 02:08:21 +09:00]])
<https://developers.google.com/photos/>

[2] [CITE@en[Get started with REST  |  Google Photos APIs  |  Google Developers]]
([TIME[2019-09-30 12:12:44 +09:00]])
<https://developers.google.com/photos/library/guides/get-started>

[3] 
[[Google Picker]] という API もあります。