I do that with my hair as well. It'll be long and then I'll just get a wild notion and cut it all off. I like the shock factor. I've had my hair shorter than the second pic you posted. I loved my short hair. Very little styling time.

Right now my hair is fairly long. I got a wild notion to grow it out, LOL Unfortunately I hardly take the time to style it, I usually throw it back in a ponytail or a clip.

I hope you like your new do once the shock wears off.