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