Graphic File Types

Images are stored on computers as files in one of many different graphics File Types or formats.

The number of different formats is a legacy from software vendors each developing their own products independently. Rather like the situation between consumer videotape formats of Beta and VHS - only there are more variations and no clear-cut winner!

It helps, to understand graphic file types if you know there are two basic types:

Bitmaps and Vector Formats. All the file types we use for digital imaging are bitmaps.

Which One Do I Use?

It depends on what you want to use an image for.

Different types of bitmap files all go about the same job (displaying your images) in a different way.

For example they employ different 'tricks' for remaining compact - a distinct advantage when sending images over the Internet. They might use an algorithm to reduce file size by 'describing' the image data in a different way. This may, or may not, discard data (and be termed lossy ). Another way to reduce file size is reduce the color depth by changing the color mode (e.g. GIF) but digital photographers should avoid such formats.

Image files may also contain one (e.g. JPEG) or more (e.g. Flashpix) thumbnails or text information (e.g. JPEG,TIFF) like IPTC headers.

So, in answer to which one is best requires knowledge of what you want to use it for. As a general rule, and this may be controversial, use JPEG. It is a lossy format but extensive tests have proven that no discernable difference exists when saved at maximum quality setting.

How Do I Identify a file Type?

On Windows computers you can tell which format a file is by its file extension (the three letters preceded by a dot, at the end of a file name). You may need to go into the view/folder options/view menu and uncheck hide file extensions for known file types to be able to see the file extension.