image uploads - progressive jpegs

4 posts by 2 authors in: Forums > CMS Builder
Last Post: November 29, 2017   (RSS)

By Deborah - November 24, 2017

So glad to see the option of creating progressive jpegs as of CMS Builder v3.08! I'm happy with that feature default for most sites, but have need to disable it for select sites.

1) Other than the following change, are there any other changes needed to disable 'progressive' save?

/lib/image_functions.php

... change this:
imageinterlace($targetImage, true);


... to this:
imageinterlace($targetImage, false);

2) If a JPEG image already saved in progressive format were uploaded via CMSB, would CMSB's resizing/resampling using progressive format result in a lower-quality finished image than if the upload was saved in baseline, instead? Maybe something I'll have to test?

~ Deborah

By Dave - November 28, 2017

Hi Deborah, 

Yes, you'd just need to comment that line in the two places it's found in that file.

And anytime we thumbnail or modify images there might be a loss in quality, but it should be mostly not noticeable.  There's a setting in /data/settings.dat.php for advanced > imageResizeQuality that sets the quality value for http://php.net/manual/en/function.imagejpeg.php to 80.  This is a little higher quality then the default.

Why do you need to disable progressive images? 

Dave Edis - Senior Developer
interactivetools.com

By Deborah - November 28, 2017

Hi, Dave.

Just to be clear - I do prefer the new default progressive image processing!

In this case I have a client who isn't happy with the resolution of a couple of their uploaded images, despite having image quality settings at "Maximum". I've requested from them a full-resolution original image for my evaluation and testing. Being able to turn off progressive mode will help me eliminate that as a cause of degradation.

Thanks for the reply and I'm all set for now.

~ Deborah