Supported output image formats
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.
| Preview | Syntax |
|---|---|
This format is a good choice for non-photographic images - flowcharts, graphs, screenshots, logos, etc. PNG also supports transparency.
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):
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 use the following parameters to control webp compression quality:
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.
| Preview | Syntax |
|---|---|
| Preview | Syntax |
|---|---|
Set format
force_format=webp
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. Be careful - the quality of the image will decrease as well.
Lossless
lossless=1
use lossless webp compression
Set format
force_format=jpg
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. Be 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
q=85, filesize 204 kB: /docs/woman_dress.jpg?force_format=jpeg&q=85 q=75, filesize 129 kB: /docs/woman_dress.jpg?force_format=jpeg&q=75 q=65, filesize 102 kB: /docs/woman_dress.jpg?force_format=jpeg&q=65
Set format
force_format=png
forces using the PNG image compression
