Using ImageMagick (shake and put away www.imagemagick.org/script/binary-releases.php#windows
), for a single file, you can do so in one line:
convert input.jpg ( +clone -background grey -shadow 80x16+8+8 ) +swap-background white -layers merge +repage output.jpg
The syntax of the shadow like this:
That is, in the example above, the opacity of the shadow to 80%, the magnitude of the erosion - 16-pixel shift of 8 pixels in X to the same Y. Increasing the first number or replacing the grey on black, achieve the desired intensity of shade, varying the second number is its size, and change the last two numbers to positioning.
To be able to handle any file, just moving it via drag-n-drop the icon on the desktop will have to create a batch file, for example - dropshadow.bat and put it somewhere where there are rights to run. The contents of such a batch file should be as follows:
convert %1 ( +clone -background grey -shadow 80x16+8+8 ) +swap-background white -layers merge +repage "%~dpn1_shadow%~x1"
The last argument (in quotes) specifies the name of the output file, in this case, the name of the original with added "_shadow". Want to change syntax here: ss64.com/nt/syntax-args.html
Then you just need to create a desktop shortcut to this batch file (drag it from Windows Explorer, hold Alt) can be used. Drag this icon image file which you have get in the same folder with a new shade and _shadow suffix in the name.