Acquiring And Opening Photos; About This Chapter; About Digital Images - Adobe PHOTOSHOP ELEMENTS 2 User Manual

Chapter 3: Acquiring and Opening
Photos
ou can acquire digital images from a
Y
variety of sources—you can create new
images, import them from another
graphics application, or capture them using a
digital camera. Often you will begin by scanning a
photograph, a slide, or an image.

About this chapter

Before you begin working with your photos, it's
helpful to understand a few things about digital
images. In this chapter, you'll also learn about the
different ways of getting your photos into
Photoshop Elements.

About digital images

Computer graphics falls into two main
categories—bitmap and vector. Files can contain
both bitmap and vector data. Understanding the
difference between the two categories helps as you
create, edit, and import artwork.
Bitmap images—technically called raster images—
use a grid of colors known as pixels to represent
images. Each pixel is assigned a specific location
and color value. For example, a bicycle tire in a
bitmap image is made up of a mosaic of pixels in
that location. When working with bitmap images,
you edit pixels rather than objects or shapes.
Bitmap images are the most common electronic
medium for continuous-tone images, such as
photographs or digital paintings, because they can
represent subtle gradations of shades and color.
Bitmap images are resolution-dependent—that is,
they contain a fixed number of pixels. As a result,
they can lose detail and appear jagged if they are
scaled on-screen or if they are printed at a lower
resolution than they were created for.
Bitmap images are good for reproducing subtle gradations
of color, as in photographs. They can have jagged edges
when printed at too large a size or displayed at too high a
magnification.
Vector images are displayed according to
geometric characteristics and are resolution-
independent—that is, they can be scaled to any
size and printed at any resolution without losing
detail or clarity. Vector objects include shapes and
text in Photoshop Elements. (See "About vector
graphics" on page 191.)
39
300%
1600%