JPEG Image Quality - how good is it?

IMagick is a native PHP extension to create and modify images using the ImageMagick API. ImageMagick Studio LLC did not write nor does it maintain the IMagick extension, however, IMagick users are welcome to discuss the extension here.
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JPEG Image Quality - how good is it?

Post by leeAberfa » 2018-04-19T20:53:51-07:00

We have been using GD2 on our server, exclusively for creating thumbnail images. I'm doing some additional processing on the full-sized images, and I am appalled at the JPEG write results using GD2. It really breaks down around reds, which I guess our human eyes are more sensitive is an example:
I created this image with Photoshop, saved with JPEG quality = 11 (photoshop's quality is from 1-12):
I used this code:

$downimage = imagecreatefromjpeg ("Photoshop.jpg");
imagejpeg ( $downimage, "php_gd2.jpg", 100);
And the resulting JPEG looks like THIS:

Now, my question is this: Will ImageMagick give me a better resulting image than this? Would someone be willing to take that first image and run it through ImageMagick just so I can see the results?

I've already asked my host to install ImageMagick on our server, but sometimes he requires several reminders. I'm wondering how hard I should push to get this done quickly.

Thanks for any and all assistance!

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Re: JPEG Image Quality - how good is it?

Post by snibgo » 2018-04-19T21:04:26-07:00

Your post has no images. Images can't be uploaded to this site, but you can post URLs.

I don't know what GD2 is.

For ordinary photos, a JPEG version can be visually identical to the source image. However, IM has a "quality" setting, which can give smaller JPEG sizes but worse quality.
snibgo's IM pages:

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