The whole point of Christian artistry or artists that are Christians is not to display an exact representation of Christ at all times, but to honor him in what we do. Christian art can be about nature and sex and life and death and hurt feelings and the entire the entire spectrum of human emotion and experience. We talk about those things because they are all a creation of The Artist. We cross the line into sinful territory when we portray God’s creation in a negative manner or in a way that is not biblically sound.
Christian carpenters don’t have to put a cross into every table and chair they make, Christian construction workers don’t need to make every building look like a church, Christian cops don’t need to exorcize every criminal they arrest or write God bless on every ticket they write. All that is required is to be like Christ, and to do their jobs to His glory. Witness as appropriate.
Same for Christian artists, every portrait painted does not need to be of Jesus, every song sung does not need to be a praise song, every story told does not need to be a gospel. All that is required is to be like Christ, and to honor him with our art. Our witness is worthless if we don’t follow those rules.
The more like Christ an artist is, the more powerful and credible his (or her) testemony will be reguardless of what their art is about.