Genomic DNA usually gives you a smear, so that is normal. I don't think what you are seeing is contamination but rather degradation. The issue is what average size the DNA is, without ladders it is hard for me to say what size you are seeing but it does seem likely to be pretty short. If your average size is less than 20kb then you are getting lots of degradation during your DNA isolation protocol.

I absolutely agree with Michael J. Benedik. Even though it is difficult to judge your gel image in the absence of ladder, I mostly get the same image and there is no problem with that.