For questions about how Android deals with generic images. Questions about photos will be better served by the "photos" tag.
An image is an artifact that depicts or records visual perception.
A two-dimensional picture, that has a similar appearance to some subject–usually a physical object or a person, thus providing a depiction of it. This is the more generic tag about "visual representations", meaning "pictures in general" – including e.g. screenshots, drawings, etc. If applyable, you should rather use a more specific tag, see below.