The first one, the redhead is cute but the second one? ULTRA HOT...wow. So what's the deal, is Shepard a male or female, or somewhere in between?
Either. They did the voice-acting with both male and female actors, so that you can choose when you play. They have the standard "poster face" image for the character, or you can customize the face to your own design. It's actually pretty flexible.
There are also many variations on the armor in-game, and in both ME2 and ME3, you can customize it by mixing and matching parts, and choosing the colors. So as long as it has a few of the standard design elements, you can actually take a lot of liberties with costume armor and have it still look "right".