I had strange results when trying to get good png compression.
I used Imagick::COMPRESSION_ZIP
Here are a few file sizes for a few compression levels.
Note the best result at 0. Also I got thrown off for a long time trying to get similar results to gimp. Make sure your image depth is set to 8, it appears to be 16 bits per channel, at least for me.
You can check with identify -verbose filename.png
You can also strip a bit more file size with $image->stripImage();
(No version information available, might only be in SVN)
Imagick::setImageCompressionQuality — Sets the image compression quality
Sets the image compression quality.
The image compression quality as an integer
TRUE în caz de succes.
Emite ImagickException în caz de eroare.
The default value fot the JPEG compression quality appears to be 86.
This example shows how to set the compression type, set the compression quality, create a thumbnail and remove unnecessary data in order to reduce file size.
This will use the following functions in reference:
$image = 'image.jpg';
$directory = '/path/to/image';
$image_location = $directory . "/" . $image;
$thumb_destination = $directory . "/t" . $image;
$compression_type = Imagick::COMPRESSION_JPEG;
$im = new Imagick($image_location);
$thumbnail = $im->clone;
Now, obviously you don't have to do so much with the variables and the file location. I only used so many to demonstrate where the images are coming from and where they are going.
NOTE: The $thumbnail->thumbnailImage(100,null); keeps the aspect ration by setting the second parameter to null. Read about this at Imagick::thumbnailImage
There is another way to create thumbnails that works quite well if you want to crop the image rather than using the entire image. Check out Imagick::cropThumbnailImage