What's the difference between a picture and an image?
Solution 1:
The OED defines them as (note these are only partial entries, as both words have several meanings. However these seemed to be the ones more appropriate for this discussion):
picture: An individual painting, drawing, or other representation on a surface, of an object or objects; esp. such a representation as a work of art. (Now the prevailing sense.)
image: An optical appearance or counterpart of an object, such as is produced by rays of light either reflected as from a mirror, refracted as through a lens, or falling on a surface after passing through a small aperture. Such an appearance may also be a mere subjective impression on the sense of sight, as an after-image (q.v.), and the negative image or accidental image seen after looking intently at a bright-coloured object, and having a colour complementary to that of the object. An image produced by reflexion or refraction is called in Optics a real image when the rays from each point of the object actually meet at a point, a virtual image when they diverge as if from a point beyond the reflecting or refracting body.
So I guess image refers more to the optical process, while picture is the actual painting/printed photograph etc.
Of course image is also used to refer to image files in informatics.
Solution 2:
I think when people say "image" on the computer they're talking about any file that is a drawing/picture/photograph, basically any.. image (.png .gif .jpeg .jpg .bmp etc.).
Whereas when people say "picture", they're referring to an actual photograph.
So a picture is an image, but an image is not always a picture.
Solution 3:
Apart from the already mentioned answers, an image is also the impression that a person is leaving in front of others. So, we often hear statements to this effect- 'You have a good image in her eyes.' I don't think Picture can replace Image here.
A picture is also used to imply a movie. So, we have Oscar for Best Picture. Now, Image can't replace Picture here.
Moreover, Picture can also be used to represent a situation, when Image can't do that. Like, They used to great together. But now the picture is all changed. They are about to get divorced.