Saving UIImage to App documents folder with "writeToFile: atomically:" increases the file size
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I have a requirement in my [iOS] app where the user can select an image from his photo library and that image is temporarily saved in to the documents folder. I was able to accomplish this part by converting the UIImage to NSData and writing it to file. The problem is the size of the file being increased than its original source file size. I copied an image of 1.7MB to photo library (Simulator) and added it to my application. The size is shown as 3.6MB in my app's documents folder. When I open it via preview.. the size is said to be "1.7MB (used to be 3.6MB)". This happens with the device also. Is there some variables I need to set for the OS to read the file size correctly? or is that my file size really increased? I use UIImageJPEGRepresentaion() method to get the image to NSData. 

Thanks in advance.