Islam resolves the contradictions by stating that in any contradiction, the later passage supersedes the earlier passage.
The problem is of course, the earlier passages were the "peaceful" Islam and the later passages were all head hacking, clit hacking, hand/foot hacking, gay hanging, kill all the Jews, passages.
True!! I learned this from Jihad Watch website
HOWEVER
This has never stopped Muslim propagandists from fooling Western liberals (taqiyya) via exclusively quoting the peaceful verses to them. Plus there actually are some 100% peaceful hippie type Muslims who only pay attention to Muhammad's peaceful verses. They have brainwashed themselves so thoroughly. One such sect is the Ahmadiyya Muslims. I have seen these goofs posting at Jihad Watch