id photo
A photo of a person's face, straight-on and from the upper shoulders, meant to be used as identification. Commonly seen on passports, licenses, and other official documentation.
In Japan, these photos are known as 証明写真 (shoumei shashin) and are taken to put on resumes for job applications in addition to other forms of identification. The typical backdrop for these photos is a solid or gradient blue. They can come in sets as in Danbooru post #6430444, or come individually as in Danbooru post #6357168.