Minecraft wiki entry for Small_Fireball, associated text: Small fireballs share the same texture as regular fireballs, visually differing primarily in size.
When a dispenser with a fire charge is placed with a block directly in front of it, the dispenser shoots through it and lights a fire on the other side.[verify]
A small fireball flies infinitely far until it hits a block or an entity, even if it is outside the player's render distance.
When shot from a dispenser, the fire charge starts out stationary and accelerates, as though it is falling rather than being launched. Fireballs shot by blazes, however, maintain the same speed all the way to the target.