Well, getting rid of it would be harder than not having them in the first place :) The only thing I can think of is to save the original image from Photoshop or whatever using the highest possible jpg settings. Before posting, I always resize my photos to 800px wide in Photoshop and use the maximum jpg quality setting so that the Am3 site doesn't have to change the image too much. Hope it helps.
Well I did a little more testing and found that to some degree my images have them as well (introduced by the Am3 site to maximise compression and thereby decrease bandwidth usage for them). But it does help at least to save your files using the highest available jpg quality before uploading.