I just ended up anchoring to the picture elements themselves (which already had IDs set) and not using separate a tags. Will take a bit of upkeep, but at least it looks right. The non-breaking spaces in the anchor tags created some alignment issues on my page. Here's the updated JSFiddle showing what I ended up with.
Thanks for your suggestions, everyone.
Instead of this in the grid of pictures:
<a id="Aanchor"> </a>
I went with this in the alpha tags at the top:
<a href="#AdamC">A</a>
(which linked to the pictures themselves below and not a separate a tag)