Usage: quality(amount)
This filter changes the overall quality of the JPEG image (does nothing for PNGs or GIFs).
- amount - 0 to 100 - The quality level (in %) that the end image will feature.
http://localhost:8888/unsafe/filters:quality(40)/https%3A%2F%2Fgithub.com%2Fthumbor%2Fthumbor%2Fraw%2Fmaster%2Fexample.jpg