As wikipedia points out:blockquote> Note that the use of the word resolution here is misleading. The term "display resolution" is usually used to mean pixel dimensions (e.g., 1280×1024), which does not tell you anything about the resolution of the display on which the image is actually formed (which would typically be given in pixels per inch (digital) or number of lines measured horizontally, per picture height (analog)). To confirm this on Photoshop, just try resizing an image...it lists height, width, and resolution--the latter of which is measured in pixels per inch (or similar units).
It's not an error, though many people now have a misunderstanding of the term "resolution" based on computer display marketing. When you use a given screen size, then you can use pixel dimensions as a proxy for "resolution," in a general comparative sense (though such things as dot size aren't included).
Yes it is an error.
The resolution of an electronic image -- in this case the image contained within the JPEG -- has nothing to do with displaying or printing. It only has to do with the number pixels and total dimension of those pixels.
The McKinnon image contains less pixels than the other image independent of any screen display. That's all one has to do to see that the McKinnon image was NOT the originating image.