ImageMagick includes a number of command-line utilities for manipulating images.
Here we will use
compare command-line tool.
comparetool is very useful. Suppose you want to test (e.g. layout, color, icons etc.) the difference between your expected design UI HTML file with actual result of JSP file, you just need to use
comparecommand. You do not need to compare with your own eyes.
First we will compare same image.
magick compare 1.jpg 1.jpg difference1.jpg
Result ⇒ difference1.jpg
White de-emphasizes (lowlight) pixels that are untouched by modifying.
Let's compare an image to one thats been modifed.
magick compare 1.jpg 2.jpg difference2.jpg
Result ⇒ difference2.jpg
The red areas of the difference image emphasizes (highlight) pixels that are affected by the image modifying.
Here is the list of ImageMagick command-line utilities