What is Image Compression?

Imagify optimizes your images, mostly with compression, in order to reduce their weight. But some of you have asked us questions:

This is what we would like to explain in this page.

The Web Keeps Getting Heavier

Radware, a web performance company, published a study in November 2013 claiming that the average web page weight has increased by 151% in 3 years.

This means that we went from a 600kb web page in November 2010 to a 1500kb page, three years later.

Perhaps it is not that bad since a heavier web is in fact a richer one. This should mean it is becoming nicer and more beautiful, right?

The growth of the average weight of webpages in recent years.

At the cost of speed

In fact, internet connections have not seen the same increase. They are becoming quicker thanks to fiber and 4G, of course.

But the increase in speed has not kept up with the growth of the average web page size. The web is becoming heavier but internet connections are not getting faster at the same rate.

Maybe you have seen it in real life : in some places where mobile access is not good, pages seem to take forever to load.

Bandwidth growth is less than the growth of the average weight of webpages.

 

This is why we launched Imagify: to handle the most important part of page speed: images.

Images Are the Heaviest
Elements of a Page

62%
This is the weight of the images on a website.

They are naturally heavy but some details cause their loading to be slower:

  • They can be at unoptimal dimensions
  • Or in the wrong file format
  • And they are not compressed by default

It is a fact: the average web page weight keeps on increasing. And the study tells us that images are the elements with the biggest increase.

It is mostly their fault if the web is heavier today. And we can see it everyday: we are getting used to full screen, crisp images and video backgrounds.

But let's focus on images because they represent nearly half of a web page's weight.

Imagify first uses compression
to make them lighter.

Why should we compress images?

An image file contains a lot of redundant data which means we could have the same visual result with less information.

This is why compression is one of the most important steps in reducing image's file sizes. It will have the biggest impact on their weight and therefore the loading time.

To do this, there are two
main compression methods

Lossless

The lossless compression methods won't reduce the file sizes by much because we don't want the image quality to be altered.

 

or

Lossy

The lossy compression methods will use advanced compression techniques in order to reduce the weight of the images but there will be a loss of quality.

 

You will have to choose between one method or another according to your needs, and the visual rendering you are expecting. But we can't recommend to always use one mode or another: the loss of quality differs for each image.

You will have to test it and see which level of compression best suits your needs.
At the end of this page we will show the difference between each method so you can see for yourself the quality of the images.

How does Imagify work?

Our service uses those three compression methods to reduce the weight of your images.

We made three levels available:

Normal level

It will use lossless compression algorithms. It means you won't see any loss of quality on your image, only redundant data will be removed.

Agressive level

It will use lossy compression techniques but tries not to degrade the quality of your images too much.

Ultra level

It has heavier lossy compression settings in order to reduce your image weight the greatest amount. But consequently you can see a bigger loss in quality.

This said, it is possible you won't see any quality loss even in Ultra level!
We have tested it on many images and sometimes you really can't tell which image is compressed or not.

Comparaison between compression levels

In order for you to see the difference between our different levels of compression we have prepared a comparison tool. You will be able to see the difference in quality between an original image and its compressed versions, or between different compression levels.

And you can choose between 3 image samples to compare the results. You will see : the difference in image quality is sometimes imperceptible.

Start compressing your images

in less than 5 minutes