Returns the data for the specified image in JPEG format.
- iOS 2.0+
- tvOS 9.0+
- watchOS 2.0+
The original image data.
The quality of the resulting JPEG image, expressed as a value from 0.0 to 1.0. The value 0.0 represents the maximum compression (or lowest quality) while the value 1.0 represents the least compression (or best quality).
A data object containing the JPEG data, or
nil if there was a problem generating the data. This function may return
nil if the image has no data or if the underlying
CGImage contains data in an unsupported bitmap format.
If the image object’s underlying image data has been purged, calling this function forces that data to be reloaded into memory.