Resolution

=Resolution and image size=

The first step in retouching a photograph in Photoshop is to make sure that the image is the correct resolution. The term //resolution// refers to the number of small squares known as //pixels// that describe an image and establish its detail. Resolution is determined by //pixel dimensions//, or the number of pixels along the width and height of an image.

In computer graphics, there are different types of resolution.

The number of pixels per unit of length in an image is called the //image resolution//, usually measured in pixels per inch (ppi). An image with a high resolution has more pixels (and therefore a larger file size) than an image of the same dimensions with a low resolution. Images in Photoshop can vary from high resolution (300 ppi or more) to low resolution (72 ppi or 96 ppi).