You cannot trust your peripheral vision. Here's a pretty good demonstration of that
That is freaky! Demons! Also the reason eye witnesses in court are the most useless "evidence". There are a lot of things that will make your brain lie to you. Most of what you remember is not factual, if you look into it. The brain tends to fill in the blank for you and you swear you saw *whatever* and remember it vividly when in fact it was something completely different. The brain makes a snap determination if a given thing is threat or no threat. If threat, it pays attention, if no threat, it makes up bullstuff to make things make sense to you (lies to you) and you go about your way.
As for the dress, blue with black fringe in the photo. Reality may be different but it appears blue and black.