'Logo' is a term generally used for a small picture that represents a company; for example, this is Apple's logo: http://gawker.com/assets/resources/2008/03/apple.jpeg
logo is a small picture that represents a company. often times logos are vector based so they can be re-sized to any size you want, no matter how big or small. most pictures are a set pixel size so they will be blurry if you enlarge them too much.
A logo is a symbol that represents a company or an organization.and Pictures represent of anything (as a person, a landscape, a building) upon canvas, paper, or other surface, produced by means of painting, drawing etc.
Logo is represents a company and it s vector file, Logo is just symbol of company and Image like big design like cartoon corrector Image made also vector file
Logo is a 'sign' before or after the picture, and it's just an image that represents something important (i.e company)
basically, logo is created by vector editing and picture/image is created by pixel editing. So, image/picture editing is special in color degradation but logo is special in shape maintenance.