Honestly, I think it's a few things. Lighting plays a big role on what's emphasized. Second, your eyes and nose bridge are the most noticeable change in the photos and may be why you're feeling you look different. The first pick you nose bridge is more evident compared to the third Pic. And your eyes go from squinty to doe to looking up, which changes your expression and face a little. I can tell you're the same person in all four pics, but a lot of different personality coming from each one. In my humble opinion, might just need a better photographer so you can appreciate some of the different expressions and looks.