Now I was max level in the PGCC, and I made a Spellsword with Greater Spell Focus Illusion. So I did the -project_image command and I got this:

Now I do have the right feats, and the character is max level. Thinking it might just be spellswords, I went over to another wizard build I had (not a spellsword), and tried to do it and everything worked fine:

So I think there might be a bug in the coding where the Spellsword restrictions are still considering the -project_image an Epic Spell Focus command.