Operation Manual

USING PHOTOSHOP

Understanding and opening images

Last updated 12/5/2011

Pixel dimensions equal document (output) size times resolution.

A. Original dimensions and resolution B. Decreasing the resolution without changing pixel dimensions (no resampling) C. Decreasing the

resolution at same document size decreases pixel dimensions (resampling).

Quickly display the current image size

If you want to quickly display a document’s current image size, use the information box at the bottom of the document

window.

❖ Position the pointer over the file information box, and hold down the mouse button.

More Help topics

“Display file information in the document window” on page 41

File size

The file size of an image is the digital size of the image file, measured in kilobytes (K), megabytes (MB), or gigabytes

(GB). File size is proportional to the pixel dimensions of the image. Images with more pixels may produce more detail

at a given printed size, but they require more disk space to store and may be slower to edit and print. Image resolution

thus becomes a compromise between image quality (capturing all the data you need) and file size.

Another factor that affects file size is file format. Because of the varying compression methods used by GIF, JPEG, and

PNG file formats, file sizes can vary considerably for the same pixel dimensions. Similarly, color bit-depth and the

number of layers and channels in an image affect file size.

Photoshop supports a maximum pixel dimension of 300,000 by 300,000 pixels per image. This restriction places limits

on the print size and resolution available to an image.

B C