Can this image be the result of a Western Blot?
I do not think that a publication quality blot should have such an artifact, but I was able to find something similar by purposely over blotting (not the same as over exposing) a gel.  If you use too much primary, secondary, or developing reagent, you can get your HRP signal to "burn in" a membrane where you get a distinct "negative band."  

By negative band I mean a region that is more clear/white than background. This happens mostly when you have way too much secondary antibody.  Normally when this happens, the CENTER of the band burns in first so you would see a white center with dark edges.  And that's only when you are imaging the membrane as it is burning in.  Often the whole band is white.

After going through the westerns of grad-student who is working with me, I found this image:



It came with the clear notation that it was burned in and disregarded (said student was learning how to do Westerns at the time).  It's a GAPDH blot for those that care.  When this does happen, it's obvious because you can then see the band with your naked eye on the membrane.  Again this would be a reason to not publish the blot.

The image could have non-maliciously been edit via compression, screens, filters, etc as mentioned by others in the comments.  This is the only way I can think of to experimentally have a similar image.  Ether way I don't think the image should be reported as is.