Putting more than one photo on the same slide
There's not a built-in way to put more than one photo on the same slide, but we're working on it! You can organize a collage of images in another app to save it as one 'picture' that can be used in Haiku Deck as a slide background. Another workaround would be to assemble images on a Keynote slide (or slides) and export the slides as images to use as slide backgrounds. You can also use software like Pixelmator or Photoshop to assemble multiple images into one file to use as a slide background.