exec/pasthru problem

i was now trying all the examples from the docs but no success yet can someone please help? i want to convert an image to another format i was fread-ing the one image into $image1 so they are binary in there and i want to pass that to imagemagick's convert, using: convert gif:- jpg:- which reads from stdin and outputs the result to stdout how can i pass the _binary_ $image1 to convert and retreive the $convertedImage reason, i want to insert the image as a blob and i dont want to mess with files thank you -- Wolfram