Enhancing Silent Image's effect with Ghost Sound

[Jack Napier]

My bad last game with my crackling thundercloud.

Since both spells have a casting time, and silent image requires concentration to maintain (meaning a standard action each round) I believe that illusionists such as Damian cannot do anything besides move and perform free actions or immediate actions while making the illusion.

However! Another spellcaster can assist with ghost sound, OR if the illusionist casts ghost sound BEFORE silent image and is good in describing what sound the spell will emulate it can use the fact that the spell lasts for a certain number of rounds (1round/caster level)

So in the example of Damian's crackling thundercloud, he would've had to make the sound of thunder cracking around the room before creating the illusion of the cloud. and then moving the cloud with the sound of crackling lasting for a few rounds. This sound would only presist 3 rounds at Jack's current Rog1Sor3 state, but later on he could do this rather effectively.