Images
The word image can also be described in broader sense, by which it can be classified in many types. These are: A volatile image: This one remains only for a fraction of time, this may be a reflection on mirror or a scene displayed on a cathode ray tube. A mental image: It exists only in mind, something one remembers or imagines;the subject of an image need not be real; it may be an abstract concept. A still image: It is a static image, as distinguished from a moving image. A film still: It is animage taken on the set of a movie or television program during production and used for promotional purposes. A digital image: It is a numeric representation (normally binary) of a two-dimensional image.
Now, if we have to standardize the organization of digital images, we have to use image file formats. Data in image file format is stored in raster or vector format. Once an image is rasterized it becomes a grid of pixels and each of them provided with a number of bits to designate its color and depth. Image file consist of digital data, which can be rasterized to use on a computer or printer.When an image is rasterized it becomes a grid of pixels and each of them provided with a number of bits to designate its color and depth. Vector images, unlike raster images, can be any dimension independent of file size. File size increases only with the addition of more vectors. Vector imagesbreak the image into a set of mathematical descriptions of shapes: curve, arc, rectangle, sphere etc., they are Resolution-independent: scalable without the problem of “pixelating”. Lastly, talking about compression, it process of reducing image file size. There are two types of image file compression techniques:lossless and lossy.Losslesstechnique reduces file size of image preserving the perfect quality of uncompressed image.Lossytechnique preserves the representation of original copy, but it is not a perfect copy, means the original quality will be lost.