Zack Snyder's The Last Photograph has been "two decades" in the making.

The 60-year-old director recently premiered The Last Photograph, the new war-thriller movie, at the Toronto International Film Festival, and he's now opened up about the long-winded creative process.

Speaking to Variety, Zack explained: "It's been, like, two decades.

"It would be one thing if it was two decades where we had done nothing else, and the truth is that most of the things that we've done have stopped us more than anything.

"I think we were working on this before 300. The reality of how we did it this time is, we had a hole in the schedule and there's another script I wrote, Illusions, based on the Richard Bach book.

"We were like, 'Should we make Illusions or should we make The Last Photograph? How should we do this?' And then we went, 'Let's do The Last Photograph. And the window was small.

"We shot this in 32 days. The thing that I credit most is the team and our own skillset of being able to mount it and do it quickly with no money."

The Last Photograph focuses on an ex-DEA operative who searches the South American mountains for his missing niece.

Zack - whose previous film credits include Dawn of the Dead, Man of Steel and Batman v Superman: Dawn of Justice - described himself as a lover of "the highest-art version of kitsch".

Asked about The Last Photograph being "very dark", Zack replied: "It's a deadly serious movie, but on the other hand, if you've seen my movies, I'm in love with kitsch, and the highest-art version of kitsch, and I don't think I ever escape that.

"As a filmmaker, I never try to escape that -- even in a work like this. I am being earnest but I'm always self-aware, and I have a hard time with straight drama without the melodramatic side, which to me is the interesting side.

"I'm always self-aware of the fact that it is a movie about a thing about a thing. I'm never not having a conversation in my mind about the fact that, 'Oh, the audience is watching these two actors talk about a thing that never happened.'"

The new film has been criticised because it features a lot of violence and brutality toward women - but Zack has pushed back against those accusations.

He said: "First of all, I would argue that the violence toward women and men is equal and that nobody is spared -- men, women, children, everybody.

"The justice that's doled out in the movie is in the same way that a hurricane doles out justice. To try and superimpose morality over it and want the violence to mean something -- the meaning is that violence doesn't work and doesn't get anything done."