It's alright for your first tries. But I'm not going to lie to you. From my point of view, it doesn't look very good. Law: Never go over 400 pixels width and over 150 pixels height when makin signatures, unless you have a good reason(Going out of the box for example).
Also, your pictures look crap because you saved them at a low quality. Set the quality to 10+ next time. Go to
http://www.pixel2life.com for some great tutorials. It's where I learned most of my stuff from.