OpenCV Unhandled exception when writing a file

Question

After trying different things, my program always crashes while saving an image. It reads well the image and I'm able to visualize it but I can't save files (it occurs in all programs that I make with OpenCV while using imwrite). It occurs while debugging in Visual Studio 10.0 with OpenCV 2.1:

Unhandled exception at 0x67570fcd in SR.exe: 0xC0000005: Access violation reading location 0x00000000.

Here the code:

Mat imLow;

imLow=imread("Cameraman256.png",0);
if(!imLow.data)                             
{
    std::cout<<  "Could not open or find the image" << std::endl ;
    return -1;
}
imwrite( "image.png", imLow);

Can anyone tell me how can I fix this? Thank you

UPDATE : It seems to be a problem with PNG and JPEG format, because the line works while saving in BMP format.

Answer 1

BMP file saving is built-in, as is IIRC .PGM, the others are provided by 3rd party libs depending on your OS.

Did you build openCV yourself? What OS?