PHP GD compressing png but not compressing Jpeg

Question

The following works very well for png files, but for jpeg/jpg the compression doesn't work.

function compressImage($source, $destination, $quality) {
    $info = getimagesize($source);
    if ($info['mime'] == 'image/jpeg') $image = imagecreatefromjpeg($source);
    elseif ($info['mime'] == 'image/png') $image = imagecreatefrompng($source);
    imagejpeg($image, $destination, $quality);
    return $destination;
}

How do I get it to compress jpeg?

jpgs are always compressed. but if you set the quality too high, the file size can be artificially increased for zero gain in actual quality. — Marc B, Apr 02 '13 at 18:10
If you're compressing it at the same quality it was originally, then it will end up roughly the same size. — Adrian, Apr 02 '13 at 18:13
I haven't already compressed the image with php and I set it quality to 80. — Joshua, Apr 02 '13 at 18:17

score 0 · Answer 1 · answered Apr 02 '13 at 18:12

0

In order to manipulate JPEG files with GD, your version of PHP needs to be compiled with libjpeg support built in. You can check this on phpinfo. Look for the following two:

JPEG Support enabled
libJPEG Version 6b (or different)

If you don't have those, ask your host.

Another issue that might come from this is that your mime type for jpeg images might come up as unknown. Double-check the library version - if it is there, comment back and I'll see if I can find a problem in your code by more than library introspection.

answered Apr 02 '13 at 18:12

Sébastien Renauld

19,203
2
46
66

His issue isn't that he doesn't have libjpeg, OP stated he can create JPEGs from PNGs just fine. – Adrian Apr 02 '13 at 18:14
Cool. I have both JPEG Support enabled and libJPEG Version 6b. – Joshua Apr 02 '13 at 18:16

score 0 · Answer 2 · answered Apr 02 '13 at 20:34

0

The issue was with PHP.

Do:

yum install gd gd-devel

answered Apr 02 '13 at 20:34

Joshua

79
1
8

PHP GD compressing png but not compressing Jpeg

2 Answers2