Good for you for posting pics!

My first thought was that the bike looks small and you look compressed. What I mean is that your upper body is quite upright and it causes the straight arms. If you wanted to assume a more aggressive, less wind resistant position, you could try a longer stem that would allow you to tilt your pelvis more toward the front of the saddle, thereby lowering your back, which then allows you to have bend in your elbows. This does require good core muscles though!

However, that being said, you may be more comfortable in more upright posture and the advise from the others is spot on.

Just my 2 cents. A longer stem did the trick for me. Trying to get lower and not having the room to do so, had me all messed up.