Import snapshot gets a dark gray tint

[David Epstein]

On Mac OSX 10.4, type "import snapshot" in the message box.  As  
expected, the cursor becomes a cross-hairs to permit dragging out a  
screen rectangle to create an image.

But on my computer the area I drag across gets tinted dark gray to  
show me where I'm dragging; and then the image created is also tinted  
dark gray.

How can I get a snapshot of the dragged area as it actually appears,  
without the dark tint?

Thank you.

David Epstein