Executive Producer Marc Guggenheim tweeted the above tweet (and pic). Now, it could just be a logo created as an Easter Egg for an upcoming episode of the show, or it could mean Ted Kord, the Blue Beetle, will making his TV debut. I'm thinking the latter, because 1) if it was an Easter Egg, Guggenheim wouldn't tweet it, he'd wait for people to find it in the show — that's how Easter Eggs work; 2) Guggenheim would have to know that by tweeting the pic fans would assume Blue Beetle will show up, so it would be kind of a dick move if it's just going to be used as a logo on some crates in the background; and 3) Kord doesn't actually have superpowers, he's just a genius inventor, so he's one of the DC heroes who can actually fit in Arrow's universe. Besides, green and blue look so good together.
One personal note: I generally consider Ted Kord to be the most boring comic book character alive, but Arrow is so goddamn good I'm genuinely looking forward to see what the show does with him. You may disagree with my assessment of the character, but this should still indicate how insanely good a superhero show Arrow is.
Another personal note: Could Stephen Amell's head be any more obviously photoshopped in the top pic? IT'S HUGE.