Spitty,
Suggest you bin your "standard passport size photo", since our standard passport size is different to the US standard.
They should have sent you a list of approved photo shops. If I remember correctly, Snappy Snaps was the only chain, and there were a few independant shops too. Go to one of these places. I went to Snappy Snaps, they had a digital camera specifically for the purpose of taking US Visa photos. It had markings all over the view-finder to show the photographer exactly where your head, shoulders, eye-line, etc, had to be. Taking the photo took, well, the time it takes to take a photo, it was printed about two minutes later, and they double-checked everything with a ruler too. Very professional, and well worth it to avoid even the slightest risk of having to do it all over again.
FFF
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