Aligning image content
You can compare images that have been resized, rotated, reflected or cropped.
Pick Auto Scale 
to automatically enlarge the smaller image to match the scale of the larger one.
Pick Rotate Clockwise 
or Rotate Counterclockwise 
to rotate the current image ninety degrees to the right or to the left.
Pick Flip Horizontally 
or Flip Vertically 
to reflect the current image across its y-axis or x-axis.
If one image is a cropped version of the other, you can drag the mouse over the difference pane to adjust the position of the right image's top left corner. To reset the offset back to (0,0) pick Reset Difference Offset or simply click on the offset label. For finer control, use the arrow keys to nudge the offset one pixel at a time, or Ctrl+arrow keys to move by a larger amount. Note that the difference pane must be selected for the keyboard nudge function to work.
Tolerance Mode
Pick Tolerance Mode 
to have difference pixels indicate matches, unimportant differences, and important differences. It uses a configurable Tolerance to define the greatest degree of difference that is considered unimportant. You can also define Replacements to ignore specific color changes between images. By default, shades of gray are used for matches, shades of blue are used for unimportant differences, and shades of red are used for important differences. You can adjust these colors to suit your preferences. (See Picture Compare Colors.)
Mark Ignore Unimportant Differences 
to ignore any differences less than or equal to the tolerance. They will be handled the same as matching pixels.
Mismatch Range Mode
Pick Mismatch Range Mode 
to have difference pixels represent the degree of difference between the images. Black pixels are used for matches and yellow ones are used for differences. Brightness represents the degree of difference.
Blend Mode
Pick Blend Mode 
to use a configurable Blend percentage to combine the images. Decrease the percentage to make the right image more dominant.