Photoshop: Image Resolution

Every Photoshop image is rectangular in shape, corresponding to a fixed measurable size (in inches), and exists at a fixed resolution (usually expressed in pixels per inch).

72 pixels per inch is appropriate for on-screen display (e. g., websites).

300 pixels per inch is appropriate for printed photographs.

600 pixels per inch is appropriate for printed vector drawings and/or text.

Image resolutions greater than 600 pixels per inch might arise in the case of scanned slides.

Use Photoshop’s Image > Image Size command to change an image’s measured size and resolution.


What is Photoshop?

Photoshop is an image-editing program – its images are composed of a grid of pixels and closely approximate continuous-tone photographs. Photoshop provides tools and commands used to edit images on a pixel-by-pixel basis.

In general, most operations in Photoshop are of the following form:

1.  Use a tool or a command to select pixels within the image.

2.  Perform an action on the selected pixels to change their color.