图片格式转化为imagedata格式
UIImage *addPic = [UIImage imageNamed: @"ko.png"];NSData *imageData = UIImagePNGRepresentation(addPic);// png// NSData *imageData = UIImageJPEGRepresentation(addPic, 1);// jpeg[picker addAttachmentData: imageData mimeType: @"" fileName: @"ko.png"];
补充:移动开发 , IOS ,