You can change the compression (output format and quality) of your image by using compression filters. You can use the compression filters alongside and .

You can of course force a specific output format(s). More details can be found in the image formats section.

JPEG compression

The JPEG compression format is suitable for delivering photographic images with minimal quality loss and high compression rate. You can either choose the compression factor yourself or use Optipress - our Machine Learning based algorithm, which will choose the best way to reduce JPEG file size minimising perceptual quality loss.

Available parameters

Examples

PNG format

This format is a good choice for non-photographic images - flowcharts, graphs, screenshots, logos, etc. PNG also supports transparency.

Available parameters

Lossy PNG compression

While the PNG format offers lossy compression only, Filerobot can optimize the image before compression by reducing the number of colors or adding slight dithering (while preserving edges). This method usually leads to smaller file sizes for images visually indistinguishable from the original ones.

You can activate this feature in the Asset Hub (Settings/Process/Images/Image compression):

Examples

WebP format

WebP is an image format maintained by Google and supported in certain browsers (mainly Chrome, Opera and on Chrome Android) which provides more aggressive compression techniques as JPG without noticeable quality degradation.

You can use the following parameters to control webp compression quality:

Examples

Deliver images in their original format

By default, Filerobot delivers the images as WebP, when the format is supported by the browser. If you would like to keep the format of the original image (when possible), you can use force_format=original.

Different images compressed with the same compression parameters may result in different perceptive quality. Moreover, the same image in different sizes may require different compression strategy to achieve maximum size gain without visible quality loss.

To overcome this, you can use our Optipress JPEG compression algorithm.

• Optipress finds out the best JPG compression approach by analysing specific image features and current compression parameters.

• A Machine Learning model determines the best compression strategy for this image.

• Quality is then evaluated based on a simulation model of the Human Visual System to achieve optimum compression without perceptive quality deterioration.

By using Optipress, you can get the most of the JPEG compression format.

Usage

Examples