Blink was developed to help Users who love to work image puzzles (find the differences between two images) but can't find all the differences. Blink is freeware.
Version 1.4.0 is compatible with Normal and Retina displays.
When you launch Blink you see the main window.
Preparation for use of Blink is easy. Use Grab (Apple screen capture application found in Applications / Utilities folder) to make a screenshot of each image (use Capture / Selection). Click on the top left corner of the first image, drag to the bottom right corner, and save as Picture1.tiff on the Desktop. Repeat with the second image and save as Picture2.tiff on the Desktop. You are done!
Note: If you are running Sierra and Dropbox, screenshots saved to the Desktop will go into Dropbox. You can either quit Dropbox or save Picture1.tiff and Picture2.tiff to a folder on the Desktop and then drag them from there to the Desktop.
Now, launch Blink and click on the "Start" button. The differences between the two images will "blink".
If you see a bit of jitter (because you did not make the images exactly the same size or start at the same exact point), just click on the Up/Down and Left/Right controls to minimize the jitter.
You can find image puzzles on the internet by searching for "picture difference game" or clicking on "Image Sources" > "Options" in the menubar and clicking on one of the ten buttons to take you to puzzle sites. One set of images is included in the zip package to get you started.
Click here to download Version 1.4.0 (6.4 MB) for Macintosh OS 10.7 or later (zip). The file includes two images and a Read Me file. Drag the images to the Desktop. Launch Blink and click on Start.
Note: Example images were made using a Normal (not Retina) display and will appear smaller than images made using a Retina display.