I want to hear your best strategies for using Project Image. Yes, I know it's cheesy and game-breaking, but I still want to know more powerful and creative ways to use it.
I have already established that it doesn't seem to be able to cast triggers/sequencers that the original caster has.
This spell obviously lends itself to a combination of mass summons/buff route and AoE spell traps. A sorceror is in the best position to make full use of this spell's power immediately, because of the higher number of lower level spells available when PI is first available, compared to a mage. At character level 14, the first opportunity when PI can be learned, the sorceror has 3 casts of PI, along with 5 of level 6 (Death Fog, Improved Haste, Disintegrate, Chain Lightning) and 6 of level 5 (Cloudkill, Sunfire, Feeblemind, elementals), which has to come close to quadrupling the sorceror's power.
The image can cast from items/scrolls in quickslots without expending them - so a certain summoning staff is also very powerful with PI, as are any extra high level scrolls one happens to have laying around.
I should also mention that a true neutral cleric/mage gets very strong usage from this spell - think 6 aerial servants buffed with Righteous Wrath among other goodies, without causing fatigue in the caster.