Page 560 - Beginning PHP 5.3

Part III: Using PHP in Practice

Figure 17-16

How It Works
The code is relatively straightforward and shouldn’t pose any problems. The
imagecreatefromjpeg() function creates a new image resource from the existing image:

$myImage = imagecreatefromjpeg( “lucky.jpg” );
Then the script sends a header to the Web browser, telling it to expect some JPEG image data:

header( “Content-type: image/jpeg” );

All that’s left to do is send the data and clean up the image from memory:
imagejpeg( $myImage );
imagedestroy( $myImage );
Of course, the script doesn’t do anything that you couldn’t do yourself using plain HTML, so you may
be wondering what the point is. Well, being able to open existing images and manipulate them before
sending them to the browser is useful for a number of reasons. Some of the things that you can do to
an image using the GD image functions include:
❑ Resizing the image to create a thumbnail for display

❑ Dropping the image quality for faster loading

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