I Corinthians 6:20
It's quite clear that the Christian God makes very little statement about the correctness of any particular personal style and expression (outside of things that are obviously wrong on a universal level). Yes, it was emphasized in the laws of Leviticus and other older texts, but was very clearly overturned — because Jesus understood that laws such as these are designed to suit times and are not universal truths.
We all know the quote from Jesus, “Do not think that I came to bring peace on earth; I did not come to bring peace, but a sword. For I came to set a man against his father, and a daughter against her mother, and a daughter-in-law against her mother in law.” (Matthew 10:34-35)
Now, some atheists choose to use quotes like this to discredit the Bible through some foolish straw man argument — but the truth is, Jesus was a revolutionary, a terrorist, and an anarchist. This statement was about the destruction of a way of life, and it's replacement with something more “true”. He wasn't an ignorant thug though — he was idealistically fighting to overturn outdated laws that effectively spread lies about the will of God (as well as on a more objective level, misleading and abusing people).
Now, I think you all know that I don't have a high opinion of what Christianity has become, but I have far more disdain for someone who tries to warp its teachings to suit their personal goals. Let me be very clear about this: God doesn't care if you're tattooed or not. It's simply not His concern. Anyone who tells you otherwise, under Christian doctrine, is quite clearly operating as an agent of Lucifer.