Quality Optimization
Image quality describes how appealing and clear an image appears to a user. Optimizing an image's quality is a way to achieve speedy delivery of an image over the internet while maintaining an optimum quality for the human eye without much degradation.
For example, there is not much visual change in an image when its quality is set at 100 or 80, but there is a huge size drop from 881 kB to 179 kB which is an order of magnitude difference.
PixelBin allows setting an image's quality between 1 (smallest size but lowest quality) and 100 (largest size but best quality). Setting an image's quality is heavily dependent upon where the image is used, the requesting device and the expectations of the user.
The option you select involves a trade-off between visual quality and file size: the lower the quality value, the more the file is reduced to a smaller file size, and the more data are lost in the process, resulting in a loss of visual quality. The loss of visual quality is scarcely perceptible to the human eye in greater-quality settings. Other variables, such as the size of the original picture and the density of the user's computer or mobile device, influence the final visual quality outcome.
There are a couple of ways to control the quality of images:
Default image quality at the zone
PixelBin uses zones and datasources to deliver your images. You can set the default quality for images at the zone level itself. Depending on the requirement, you can create different zones with different default quality settings all of which point to the same datasource.
In the Optimization tab of a zone, first, enable the Compress Image switch and then select one of the quality options from the dropdown.
- By default, PixelBin does not compress your images when transforming. They are at their highest quality level.
- The default quality setting will only work on transformed images. Click here to see how to apply compression on original images.
- If format optimization is also enabled for the zone, compression will be done after the format optimization.
Set your default quality to less than 100. Setting the quality at 100 will result in a bigger file size with no discernible increase in visual clarity.
Image quality when delivering
You can specify the quality level as a transformation when you want particular image transformations to use a quality setting that is different from the default setting in your zone, or when you are not performing any other transformations on an image you deliver.
The Compress transformation allows you to control the visual quality and compression level of images. This will override the default quality setting in your zone. This is useful if you want to deliver all of your images at the same quality while modifying the quality of a few chosen images.
For example, compressing the image with quality at 80 percent.
https://cdn.pixelbin.io/v2/dummy-cloudname/FIDrmb/t.compress(q:80)/images/optimization/jet.jpgClick here to learn more about compress transformation.