The first two - they are weird, to say the least. I suggest using a tablet, and a program like GIMP (or maybe even Photoshop) would be a good thing to have. Practice, practice, practice. Also the pictures need to have some anti-aliasing done to them. And the facial expressions - try drawing anime over and over again, because you need practice. And don't worry! I wouldn't have been able to done it myself tbqh. But that being said, it needs improvement.
As for the banners, the pictures also need to be anti-aliased. Wether that be by changing the settings or filling in every pixel, that white ring around some objects shouldn't be there.