, sorry for my bad English. Let me try again.
The original image was a hi-res portrait of me standing at the phone. I used IrfanView to crop the area with my face then resized it to make avatars. As you can see, two of them – in spite of the crop/resize – still show the whole original image content when viewed as thumbnails in Windows (the attached image is a screenshot from Windows Explorer and the numbers in the files names are the images size in pixels).
So if I open avat_160x160 or avat_180x180 with IrfanView or Windows Photo Viewer, it will show only the area with my face (like on the other images), but if I view them as thumbs in Explorer they appear as thumbs of that original hi-res image.
See another example from my avatar here at the forum: the original image was a portrait of people from my workplace. I cropped and resized to get a square with my face. But two of the new images thumbs show the original portrait content...