If the image is not a link, than the border can be used as a tasteful outline , as opposed to the vexing purple outline. Give your photos space of their own. Placing images too close together makes it difficult for your eye to focus on one image only, for example on this page of excellent Jere DeWaters photos . If you're working with small thumbnail files that are primarily intended for navigation then using white space isn't such a concern, since all viewing will be done at the larger size. But viewers looking at medium size images might not choose to download a larger version, so all they'll see of your work is the smaller, crowded image.
Drop shadows add depth to the image without taking up much space.
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