Resizing/Resampling

Example 1

resample
resize
resize compare

For this example, I created two graphics, both 100 x 100 pixels. I then resampled the red line to 50x50 and resized the blue line to 50x50. to make them large enough to show the distinction between the two methods, I zoomed in 5:1 and 'captured' both images. I combined them into one graphic for ease of comparing the two lines. The red is resampled and the blue is resized.

Which method should I use?

Resize simple and hard-edged images such as text and graphic art. Resizing duplicates or deletes pixels while Resampling smooths out rough spots by estimating how the "missing" pixels should appear, and filling them with the appropriate color. (See the example 1 above).

Resample photos and photo-realistic images or complex images.

Example2

resample
resize
resize
Example 2 shows the same photo resampled and resized. Even with this size you can begin to see deterioration in the resized image. To better show this deterioration, I've taken a section of each graphic and zoomed in at a ratio of 2:1. Each sampling was then sharpened once. It is very evident in example 3 that the quality of the resampled image is superior to the resized one.

Example3
resample	resize

Why is my resample option greyed out?

The Resizing option is always available, but the resample option will be greyed unless your image is greater than 256 colors or is greyscale.

If you find that your resampling option is greyed out, increase your color depth to 16 million colors, resample the image and decrease the colors when you are through editing.

All this is great...but how do I do it?

Resampling and Resizing are similar in procedure and both offer two methods of changing your image size; by height and width or by aspect ratio.

Height and Width

There are two ways to select a height and width, use only one of them. On the left of the resample/resize boxes are five standard image sizes. You can select one of these by clicking on the radio button or text , or you can specify the height and width in pixels by selecting the custom size option.

Custom Size By Width and Height

Click on the Custom Size Option.
Deselect the Maintain Aspect Ratio Checkbox.
Type the new width into the first text box.
Type the new height into the second text box.
Click OK

Note: Be aware that this method will probably distort your image.

Customize By Aspect Ratio

The aspect ratio is the relationship between the image's two dimensions, expressed as width divided by height. To specify a custom size using the aspect ratio:

Click on the Custom Size Option.
Select the Maintain Aspect Ratio Checkbox.
The Aspect Ratio Text Box will display the image's current aspect ratio. If you want to change this ratio, double-click in the text box, and type the new ratio.
Enter the setting for the dimension that you want to fix. (Note: You can adjust the height setting allowing the aspect ratio to determine the width, or you can adjust the width setting allowing the aspect ratio to determine the height. The setting you do not adjust will be automatically updated when you click on the OK button.

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