Greetings! Welcome to BYC!
EEs are very difficult to sex by photograph because they don't have sizeable comb development. I might be able to tell from a pic of the way he/she stands - but you may be able to determine better than I because you can watch for certain behaviors. Little cockerels tend to stand more erect. They also tend to be more social and outgoing than pullets. There are always exceptions to the rule, but generally speaking, those are some of the signs for which to look!! Cute little flock!