Setting lower quality increases the file size

# Expected Behavior

Decrease the file size with decrement in image quality.

# Current Behavior

Increase the file size with decrement in image quality.

# Code
```
jimp.read("./forest-patrol.jpg", (err, lenna) => {
if (err) throw err;
lenna
.quality(60) // set JPEG quality
.write("./forest-patrol-jimp-mini.jpg"); // save
});
```
Here, we can see that original image forest-patrol.jpg is smaller than the processed image forest-patrol-jimp.jpg