According to Osho, you should not hold any image to concentrate in kirtan; the goal isn’t concentration but dissolution. Let images arise or fade without grasping, and surrender to absorption—melting like ice into a river—until the ego, thoughts, and even sacred forms dissolve into the formless, the oceanic feeling where only the One remains.
Don’t pick a picture; just sing and let yourself melt into the music until even the idea of “me” disappears into a big peaceful ocean.