First of all, we need to broaden the view and try to understand an image file as a set of data and pixels.
Within each JPG, JPEG, PNG, GIF or other file image file, there is metadata and repeated information. The work of compression is just removing this redundant information to reduce the weight of the file.
When the image is compressed, instead of having multiple equal and repeated pixels, it stores only one value of that pixel, which is reproduced for similar ones, saving loading time.
There are two forms of image compression:
Compressing images at lossless is the perfect option for those who need the highest quality at all costs. Usually used by photographers, lossless image compression is done with file extensions with more features such as TIFF and PNG and to add to that, no data is lost.
The recommended compression format for web results in a small drop in quality. So small that it is little noticed by the human eye. With Lossy, you can optimize the image by up to 90% of its original size depending on the cases, but here, data is lost. JPG, JPEG, and GIF are the most popular formats for images with this type of compression.
Which One to Use? Will Compression Greatly Affect Image Quality?
If you need a high-resolution image to print, yes, it will affect quality.
However, if the use is only for the website or blog of your company, the indicated one is to compress because the reduction of quality is practically imperceptible to the naked eye, but you can also learn how to make an image smaller.
Why Reduce the Weight of Images?
There are several benefits to maintaining a website with optimized-sized images.
· Sites Slow and With Heavy Images
If the option is still to maintain the images in supreme quality, it is possible to optimize the site using smaller miniature images, and that can be enlarged, then in high quality, with the intervention of the visitor.
· Lighter Sites Drive More Conversions
To prove the subtitle theory above, we’ll bring a study done by Mozilla in 2010. At the time, the company realized that conversion rates on landing pages were also associated, to some extent, with page load time.
In an A/B test, the company noticed that a 1-second increase in page load time corresponded to a 2.7% drop in conversion rates.
So, Mozilla cut 2.2 seconds of the landing page of Firefox. The result was a 15% increase – or 60 million – in the number of browser downloads.
· Lighter Images as SEO Strategy
It has been proven that as an SEO strategy, having a website takes some help in ranking Google.
The loading speed of the site is one of the criteria taken into account by Google and can define – whether or not it favors – its position in the SERP.