Category Archives: ShortPixel updates & news

Google’s Guetzli vs. ShortPixel’s Glossy algorithm

Guetzli vs ShortPixel

Guetzli is the new JPEG encoder developed and released as open source by Google. It is designed to produce ~35% smaller files, without compromising  the picture quality. We, at ShortPixel, had recently our own update: ShortPixel Glossy optimization, the lossy new algorithm for photographers.

Testing Guetzli algorithm was mandatory for us. When you are in the image compression business, you need to get your hands on any brand new innovation and see what it can do.

How does Guetzli compare with ShortPixel’s new Glossy image optimization algorithm in terms of quality and performance? Can we use it alongside our algorithms? Does it have practical value for our users?


Testing conditions

Guetzli was tested on a quad-core Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz processor. We used Guetzli setup with two parameters: 84 and 95. 84 is the minimum quality allowed by Guetzli, and 95 is the default setting (in this case, a bigger number means better quality and larger files).

As we mentioned before, Glossy is our new image optimization algorithm for photographers. The images optimized this way look brilliant  while being considerably smaller than their Lossless version.  Glossy optimization algorithm runs on ShortPixel cloud servers, where your images are also optimized.

The images compressed in this test are from the amazing Unsplash website. You can find all files, both originals and processed, in the attached archive. At the end of this article, you can also see the complete image credits list.


Guetzli VS ShortPixel: test results

Image size improvement, compression speed and picture quality – these are the most important factors we gathered for this comparison.

File size improvement
ShortPixel Glossy produces smaller images than Guetzli at 95 setting for all tested images, and it has an overall improvement comparable with Guetzli 84.

 OriginalGuetzli 95Guetzli 84ShortPixel Glossy
Img-15 MB1.7 MB1.1 MB804.6 MB
Img-29.3 MB2.5 MB1.2 MB1.5 MB
Img-31.4 MB485.1 kB250.7 kB97.1 kB
Img-45.6 MB1.5 MB778 kB1.4 MB
Img-535.5 MB10 MB6.1 MB6.5 MB

Optimization speed
Speed performance is Guetzli’s weakest point. Google encoder needs several minutes to process the images, while ShortPixel takes seconds to optimize the same files.

 Guetzli-95Guetzli-84ShortPixel (Glossy)
Img-19m 01s9m 40s 8.7s
Img-29m 29s6m 30s 6.5s
Img-37m 56s4m 53s 3.2s
Img-47m 02s7m 45 6.4s
Img-531m 33s25m 47 26.8s

Picture Quality
Our users are not scientists, they don’t use image analyzing software, they simply look at images and decide for themselves if they look good or not.

Look at these 100% cropped images and see the differences between Guetzli processed files and the images optimized with ShortPixel Glossy. Remember that WordPress has its own compressing settings and the best way to compare the images optimized with different algorithms is by looking at the full sized pictures found in the attached archive.

Image comparison


image 2 - guetzli glossy optimization comparison



Please click here to download the archive containing the full sized images.


Google has a lot of talent resources, and it is not surprising that their algorithms are smart. Guetzli produces good results.

Picture quality is really good when the encoder is setup at 95, but files are pretty big. Changing the option to 84 brings a decrease of picture quality as you could see in the above examples.

Images optimized with ShortPixel Glossy algorithm have a picture quality close to Guetzli-95, but with a pretty good quality-compression ratio. Remember that we recommend ShortPixel Lossy optimization if you want Google PagesSpeed Insights improved results.

The biggest issue of Guetzli in our opinion is the incredible amount of time it takes to deliver the results. You need a computer with a lot of power to run it, and it is very slow. Developers could tweak its parameters, but we are not sure if Guetzli is a practical solution for regular users.

We are not so happy with this conclusion, because we considered useing Guetzli alongside our algorithms. Currently that is not feasible: it takes too much time and processing power to deliver results that are comparable (if not worse) that those delivered by ShortPixel’s Glossy.

Get your image optimization tool of choice!
Finally, you are the jury, and you decide which tool is the best choice for you.

Get ShortPixel from
(or install it directly from your WordPress dashboard, search for “shortpixel”).
Download Guetzli from the Google GitHub page.

Image Credits

Img-1: andrew-phillips-22066.jpg
Source: Andrew Phillips

Img-2: cloudvisual-208962.jpg
Source: CloudVisual

Img-3: miguel-mateo-212333.jpg
Source: Miguel Mateo

Img-4:  mitchell-hollander-205952.jpg
Source: Mitchell Hollander

Img-5: robert-zunikoff-53898.jpg
Source: Robert Zunikoff

How ShortPixel credits work within your account

Immediately after setting up your free ShortPixel account, you are given 100 ShortPixel credits. Each credit allows the automatic processing of one image or thumbnail (or PDF) from your WordPress web site (or sites as you will learn below). Each and every month, regardless of whether you purchased a stack of credits from the “one-time payment” section (below the monthly and yearly plans in the Control Panel), you are given an extra 100 credits to use for free. In addition, you can get an extra 100 credits per month for every person that you refer.

In your account, even while on a free or paid monthly plan, you can still always buy one-time ShortPixel credits. Important to note is that your monthly credits will always be used first.

You connect your WordPress blog to your ShortPixel account via your personal API key. This key maintains a secure connection between your site and the ShortPixel servers to keep the credit information in synch and to process your images.

You may, at any time, switch from the Free Plan (of 100 images per month) to any of the larger plans, which now includes a yearly plan. Naturally, the larger the plan, the more savings that you achieve.

On the left side of the screen, when logged into your ShortPixel account, you will see the details of your chosen plan. There will also be an indication of when your credits reset (see the image below). It depends on the date you signed up as to what the renewal date will be. When on a monthly or yearly plan, any unused ShortPixel credits will *not* be carried over, an important distinction over the “one-time” credits discussed below.

ShortPixel credits info

Note: All of your WordPress web sites can utilize the same API key, so therefore can benefit from the same pool of credits.

Non-expiring ShortPixel credits for a one-time fee

While the monthly image processing plans offer an essentially set-it-and-forget-it approach because they top up automatically, there is also the option of choosing to purchase a pool of credits for a one-time fee. These credits never expire. You will see your credits and stats for these purchases in the “One-Time Quota” section on the left side of the Control Panel, just below the “Monthly Quota” section (see the image below). The information provided includes: Bought, Used, and Remaining. You can top up on your credits at any time and the “Bought” number will increase as expected. And again, all of the web sites that utilize your ShortPixel API Key will take from this pool of credits.
ShortPixel credits info after package bought

To summarize, you can use ShortPixel for free at a rate of up to 100 images processed per month (or more when referring friends). Or, you can benefit from a monthly plan. Monthly plans do not carry over to future months. Your quota is simply reset. When purchasing one-time ShortPixel credits though, your credits never expire. And, as expected, the more ShortPixel credits you purchase (from either pricing mechanism), the cheaper it is per credit. Appropriately, monthly credits are used before one-time credits.

You can keep track of your plan and credit details either from the Statistics tab (first go to: Settings >> ShortPixel) within WordPress, or from the Control Panel when logged in at (Login here:

Hello @WordPress community!

It’s been a shifting turn for us to start a project that is mainly designed for WordPress users. And I must say, it feels good to be part of such a nice crowd! I’m also excited to finally say hello to everyone we’ve met so far along the way, and tell our story.

We’ve started to build ShortPixel over a year ago (just realized) and many things have happened since. Some of these moments should not go unnoticed, so I’ll recall some of them here below.

I̶m̶a̶g̶o̶o̶s̶e̶   ShortPixel was born. With a twist.

The original name we had in mind for our service was ‘Imagoose’—it sounded funky, but when written down, it became clear that it was a bad choice to address our users this way. Our logo was originally a constipated feverish robot. Meanwhile, we gave it a chill pill to change this frightened look.

ShortPixel old logo

Continue reading Hello @WordPress community!