Graphics Programs Reference
In-Depth Information
To determine how wide a web image should be, separate the total number of screen pixels into sections, and
specify the percentage of the screen you want the image to occupy. For example, if you want the image to oc-
cupy half the screen (remember, browser windows are typically about 900 pixels across), type
480
into the
Width text field in the Pixel Dimensions section of the Image Size dialog box; for one-quarter of the screen,
type
240
, and so on. You should also remember that the pixel size will not change, regardless of the ppi resol-
ution of your image. So, 200 pixels in a 300-ppi image occupy as much window space as 200 pixels in a
72-ppi image.
At this point, you can determine the approximate size of the optimized images. In this example, you will
use the grid feature separated into percentages to help you determine the size of the images.
4
With
advps1002.jpg
open, choose View > Show > Grid. A grid appears in the image area. You will
now adjust the grid size and units of measurement.
5
Choose Edit > Preferences > Units and Rulers (Windows) or Photoshop > Preferences > Units and
Rulers (Mac OS).
6
Select Pixels from the Ruler drop-down menu.
7
Before exiting the Preferences dialog box, choose Guides, Grids & Slices from the list of items on the
left side.
8
In the Grid section of the Guides, Grids & Slices dialog box, type
100
in the Gridline Every text field
and choose percent from the drop-down menu.
9
In the Subdivisions text field, type
8
and click OK.
Each of the four grid subdivisions represents 100 pixels; you can use this value to determine the size
you want to optimize your image to.
Set up the grid lines to appear in eight subdivisions.
Adjusting the image size
