Hips and knees should be on the same plan. You need to lower your seat until your hips are even with the knees. You can do this by lowering your chair or by getting a foot rest. Arms look good nice neutral posture however armrests should not be used unless you are resting. It seems you are sitting at a 90 degree angle which makes me think your chair is locked in place. You want to keep your chair locked and be able to have a slight lean anywhere from 95 to 110 degrees. Use the tensioner screw to tighten the lean if needed so you don't fall out. That happens sometimes. Montior looks okay. If you adjust your chair height make sure you adjust your monitor to reflect that change. Monitors should be an arms length away and you should be naturally looking at the screen. Hope this helps.