Understanding Image Resolution - Why Are My Images Filling Up My Hard Drive!

A graphic image or digital image has a boundary of resolution, which is an image's height and width by pixels. The dpi (dots per inch) or ppi (pixels per inch) also determines the resolution of an image, but does not affect its file size.

All monitors that have multimedia medias for display have a dpi of 72. This is a standard resolution, but it may not do justice to the image on the Internet - especially if it is highly detailed. It is a very low resolution, and if is printed out it will appear either smaller than the original, or it will print out poorly. The higher an image's bit-depth, the better the quality of the picture will be, yet higher quality image files have larger files. Lower bit-depth images are often lower in image quality, yet have smaller image file sizes.

Web designers keep the resolution of images at 72 ppi not only because it produces a sharp image on a computer screen but also the picture will download quickly because the picture is not weighed down by the weight of pixels.

People who want to buy a digital camera need to understand what resolution is because it is this term that decides the quality of an image, and if they want a high quality image they need a camera that an do the job. They also need to understand what pixel is because the resolution of an image is expressed in terms of pixels per inch and that of a digital camera in terms of megapixels.

The term pixel itself is derived from the words "picture element" and is used to refer to the smallest dot in an image that is used to store color. One million pixels go to make a megapixel, and a camera that shoots a picture that has one million pixels is said to have a resolution of 1MP or one megapixel. Similarly a camera that can shoot a picture that has five million pixels on its surface is said to have a resolution of 5 megapixels. Depending on the purpose of the photograph, some photographers have a few cameras to meet the needs of different jobs.

A higher resolution camera therefore provides better picture quality. That is why professional photographers use cameras whose resolution ranges from 14MP to 22 MP. These photographs are not only sharp and clear but also print well. They can also be easily enlarged without losing sharpness or focus.

In contrast, it is difficult to improve the quality of low-resolution images. The photographers are forced to add pixels through a process known as interpolation. In this process, an intermediate color is assigned to the added pixels, which is based on the color of the existing pixels. This process can add to the resolution, but not to clarity. The reason for this is that you cannot create something from nothing.

Interpolation is a common feature on low-priced, entry-level digital cameras that most beginners start with. The lower the actual resolution of the image, the lower the clarity of the interpolated image will be. Usually a 3.2 megapixel digital camera will provide images with sufficient resolution for general photography when first starting out. However, eventually when we get into photography that is more serious, we will need a camera with a higher resolution.