Actually, it is a percentage of signal quality for the quantizer to aim for. While the result is compression, what you set there is the amount of signal loss you deem acceptable.
I can not confirm your words, but I trust the documentation
A Number between 0 and 1 indicating the image quality to use for image formats that use lossy compression such as image/jpeg and image/webp.
If this argument is anything else, the default value for image quality is used. The default value is 0.92. Other arguments are ignored.
Actually, it is a percentage of signal quality for the quantizer to aim for. While the result is compression, what you set there is the amount of signal loss you deem acceptable.
I can not confirm your words, but I trust the documentation
That is exactly what I was referring to: you set the quality of the image in a lossy codec, not the compression factor (though both might coincide).
Got it )