save image with 300dpi

I want to save image 开发者_StackOverflowfiles in NSHomeDirectory()/Documents in format JPEG. Those images are edited inside the application, inside a UIImageView.

I am able to save files perfectly with: [UIImageJPEGRepresentation(theImageView_.image, 1.0) writeToFile:thePath atomically:YES];

Is there any way I can save the image with a better DPI? Say, for instance the image that is loaded and manipulated was originally of 72dpi, now can I save it with a dpi of 150 or 300 ?

Thank you