Black screen after exporting (from Vray)

hi guys,
when i render a image in vray i am getting a perfect view of my model. but when i save the image as an JPEG or PNG file i am getting the image with a black layer over it in my files. Why does this happen and how can i fix this? what is also strange is that when i zoom in on my png or jpeg the picture gets brighter. still with a black layer but less then when i have the full picture in my screen.