image util

[Timothy C. Phan]

Hi,

  Is there a utitily to check to see if a image (gif, jpg, tiff,
  bmp, etc) is good or bad interm of checksum of the file
  is OK.  I want to run this at command or in a script as:

    if [ check_image this.jpg ]; then
      echo "this.jpg is OK!"
    else
      echo "this.jpg is NG!"
    fi

  Thanks!

Timothy C. Phan