Image formats

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.

filter
force format force_format=jpeg forces using the JPEG image compression.
quality q=X
X = 0..100
the smaller the value of q, the more your image will be compressed. Careful—the quality of the image will decrease as well.
optipress optipress=X
X = 1..3
chooses the best compression approach maintaining visual quality via the Optipress algorithm.

Original image

//store.filerobot.com/fusqadtm/docs/woman_dress.jpg

filter value file size
none 330 KB

Compressed with JPEG

/docs/woman_dress.jpg?force_format=jpeg&q=90

filter value file size
q=90 282 KB
q=80 141 KB
q=75 125 KB

The JPEG compression does not support transparency. For alpha channel support, use WebP or PNG instead.

PNG format

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

filter syntax
force format force_format=png forces using the PNG image format.

Example

/docs/Filerobot_Logo_3000px.png?w=800&force_format=png

WebP

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.

By default, automatic WebP transcoding is deactivated. If you choose to activate it, all images will be delivered as WebP. If the client's browser does not support this format, JPEG or PNG (if image has alpha channel) is used instead.

You can force delivering your image in WebP by using following filters:

filter syntax decription
force format force_format=webp forces using the WebP image format.
quality q=X
X = 0..100
the smaller the value of q, the more your image will be compressed. Careful—the quality of the image will decrease as well.

Force WebP format, 263 KB

/docs/boat.jpg?force_format=webp

Please note that if you force WebP compression with the force_format=webp and the client does not support this format, image will not be displayed.

Deliver images in 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, you can use force_format=original.

Original image

/docs/boat.jpg?w=400

Here, the original image is JPEG and by default, the resized version is delivered as WebP, if possible.

Force using original format

/docs/boat.jpg?w=400&force_format=original

Now, the processed image is forced to keep its original format.