Modified version of "Rapid, Detail-Preserving Image Downscaling"
dpid-gui <input-filename> [output-width=128] [output-height=0] [max-lambda=1] (<required> [optional])
dpid <input-filename> [output-width=128] [output-height=0] [lambda=1.0] (<required> [optional])
dpid(<input-filename>[, output-width=128][, output-height=0][, lambda=1.0]);
dpid "myImage.jpg" // downscales using default values
dpid "myImage.jpg" 256 // downscales to 256px width, keeping aspect ratio
dpid "myImage.jpg" 0 256 // downscales to 256px height, keeping aspect ratio
dpid "myImage.jpg" 128 0 0.5 // downscales to 128px width, keeping aspect ratio, using lamdba=0.5
dpid "myImage.jpg" 128 128 // downscales to 128x128px, ignoring aspect ratio