One continual problem with clients is that they tend to upload 5MB images directly from their devices onto their websites. Best way around that, since we can't really enforce proper image sizing and cropping, is to magically do it with a wordpress function.
// add new Image sizes
add_image_size( 'sqr-thumb', 450, 450, true ); // Hard Crop Mode
Here's a custom image size being added, a 450 by 450 crop. Now it works, it's beautiful, BUT, the image coloring and quality has changed drasticly.
In the following image, I am calling the medium of both images (not the sqr-thumb, but if I were it would be square).
The one on the right was added prior to the custom image size. The one on the left was added after the custom image crop (it has a sqr-thumb version). I used the same image in both instances for uploading.
Obviously the one on the left is of lesser quality and coloring (as much as you can see in a black and white sample).
Is there a way to do this and maintain the image quality?
The image being used here is a PNG, saved RGB, created via Photoshop Creative Cloud. It can be found at: http://rehost.ca/temp/woman.png
Note: I've tried this with 6 different pngs, color and black and white. Happens with all of them.
Our development server uses GD.