quality property
Quality parameter is for jpeg only and is in range 0 to 100. If -1, then settings from hibernation are used. In case when the Image Ref was created with a lazy load mode and originally has the same format as the requested to save, then setting quality to -1 leads to simply copying from source to destination, which is time efficient and prevents quality loss caused by jpeg encoding/decoding.
Default is -1
Implementation
int quality;