JPEG quality settings

The compression algorithm for JPEG has a quality setting which defines the level of compression to be done. The larger compression results in smaller file size. The quality shall be between 1 (low quality, small file size) to 100 (high quality, large file size).

#Example on using quality settings

Here is an example on how the quality settings affect the file size and the visible image.

The measurements in the example is based on ?src=kodim23.png&save-as=jpg. The original image is PNG and weights 820KB. The image is resized to &w=300 to make it fit in the table and to give you a hint of the visible change while using the option for q.

What  Quality File size The image
&q=100 100 354KB
&q=90 90 100KB
&q=80 80 63KB
&q=70 70 49KB
&q=60 60 41KB
&q=30 30 26BK
&q=10 10 15KB
&q=1 1 10KB  

The default value for q is 60, its perhaps rather low to start with.

Post processing of the JPEG image, using an external tool, can further decrease the file size.