//NSData轉(zhuǎn)換為UIImage
//OC
NSData *imageData = [NSData dataWithContentsOfFile: imagePath];
UIImage *image = [UIImage imageWithData: imageData];
//UIImage轉(zhuǎn)換為NSData
NSData *imageData = UIImagePNGRepresentation(image);
//UIImage轉(zhuǎn)換為 JPEG 圖片的 NSData 第二個參數(shù)代表壓縮程度 取值范圍 0 到 1
NSData *imageData = UIImageJPEGRepresentation(image, 0.4f);
//swift
var sourceData = NSData.init()
var image = UIImage.init(data: sourceData as Data)
var data = UIImagePNGRepresentation(image!)
