If it has one bump slightly above the vent its female, if its male it should have two bumps on either side. However at that age it may be hard to tell to the untrained eye, once you learn how to tell it can be fairly easy.
The pictures arent the best, try to take another one. With them on a flat surface, lift their tail up a bit enough to show the vent somewhat.
It's hard to say with that angle as mentioned. A photo facing away with the tail arched up to show the vent will help although it can be tough to tell at such a young age sometimes. Using a flashlight can help in some cases https://www.beardeddragon.org/forums/viewtopic.php?f=1&t=204533
Yeah, no way to know with that photo at all. Put him on all-fours and look at him from behind. Then arch his tail way over his back as far as it will go (like a very happy dog) and take a photo of the area on the bottom of his tail, right above his vent.
Also hard to tell from the picture if you are, so if not I apologize, but please don't ever hold him on his back upside down. They can't breathe properly when they are on their backs.