There are no right or wrong images. Trust your inner wisdom to bring you what you need. Add more detail using color, sounds, smells, textures, tastes. Look at what's upclose and what's off in the distance. Don't limit yourself to reality.
Imagery can take many forms.
While you might want to use a realistic imagery when practicing for an athletic event, maybe a cartoon image would work better for healing. Experiment, use your imagination, use what feels right. Let yourself feel the good emotions connected with achieving your purpose. Use both inner feelings and outer expressions. For instance feel the deep satisfaction of accomplishing your goal.