I'm not that attached to the idea, so I'll stick with concentration, though I'm still thinking I might allow an exception for illusions. The list of illusions that require concentration would be...
- silent image
- blur
- invisibility
- phantasmal force
- shadow blade
- silence
- fear
- hypnotic pattern
- major image
- greater invisibility
- phantasmal killer
- mislead
- mental prison
- project image
- illusory dragon
- weird
... so I'm still thinking about how bad the potential conflicts there are. I just like the idea of being able to hide in the painting and send a
silent image of yourself down the hall. It's not an ability I'm deeply attached to, though.