The image below shows 7 x 7 grey circles which all but one share a common attribute. Can you see this shared property, or rather: Can you see which circles does not belong to the group and give a reason?
A complete answer must of course contain an explanation. To identify the circles, simply number them, i.e
3rd column, 5th row or such. I did not want to complicate the image with labels.
Note, you do not need to look at the digital content or super high resolution, nor do you need any digital processing of the image. It also contains only 8 distinct colours.