What's the Compare images feature for?

[Paultx]

Version 4.60 brought New option in File menu: Compare current image with another image.

I couldn't figure out how I can use it. For instance, I open two different images, but the dialog box options give me no clue on what I can compare.



Would someone please give me a practical example of its usefulness?

It may be even obvious for some of you guys, but I confess I don't see it.

TIA.

[Bhikkhu Pesala]

Compare two versions of the same image to see the effect of compression on quality.