What is an Image?

What's in an Image?
There are many different image file types, there is;
TIFF, PNG, GIF, JPG, RAW, BMP, PSD, PSP, etc. All of these image files are different and all have different purposes.

JPEG (*jpg; *jpeg; *jpe; *jifi) -JPEG File Interchange Format
JPG is mostly used for photographs and simliar toned images that contain lots of colour. It maintains very high image quality. JPG works by analyzing images and discarding kinds of information that is least likely to be noticed. Better graphic programmes, such as Photoshop and Paint Shop Pro allow you to view the image quality and file size as a function of compression level, so that you can conveniently choose the balance between quality and file size.

Below is an example of a JPEG image;



GIF (*gif) Graphics Interchange Format
GIF was developed by CompuServe to show images online before JPG and 24 bit colour was in use. GIF uses indexed colour, which is limited to a palette of only 256 colours. GIF files do not store the image's scaled resolution ppi number, therefore scaling is necessary every time one is printed, but this is not important for screen or web images. GIF is an excellent format for graphics, and it's main purposes are; logos, dialog boxes etc which use few colours.

Below is an example of a GIF image;


BMP (*bmp; *db) Windows Bitmap
There isn't really a reason to use this format. BMP is an uncompressed proprietary format invented by microsoft.

PNG (*png) Portable Network Graphics
PNG is a losless storage format. However, in comparison with common TIFF usage, it looks for patterns in the image that it can use to compress file size. The compression is reversible, so the image can be recovered the exact same as before.

TIFF (*tif; *tiff) Tag Image File Format
Tiff is a file format for storing images, popular among graphic artists, both amateur and professional photographers in general and the publishing industry. It was originally created by the company Aldus but since 2009 is under the control of Adobe Systems. The TIFF format is widely supported by image- manipulation applications, by publishing and page layout applications, by word processing, faxing, scanning, optical character recognition and other applications.

WMF (*wmf) Windows Metafile
WMF files are used to store vector and bitmap-format image data in memory or in disk files for later playback to an output device.