Our app pulls image search results from over 35 million Creative Commons licensed images that are publicly uploaded and tagged by internet users on Flickr.com. When you do an image search using Haiku Deck, it's essentially like doing a search for Creative Commons-licensed images on Flickr.com (unless you're on the iPad, in which case, paid premium images from Getty Images also are available in the results but are indicated by a dollar sign in the corner).
Completely separate from using Haiku Deck, you can always do a search on Flickr.com for Creative Commons photos to use in all sorts of projects. To do this:
1. Go to Flickr.com.
2. In the search field in the top right, look up whatever kind of photo you're looking for.
3. When the search results load, click the "License: any license" drop-down at the top of the results, and choose "Creative Commons only," or "Commercial use allowed" if you're planning on selling your final product or using the photos in a commercial project.
4. When you click on any of the new search results, the type of license will appear on the right. You can click it to learn more about what types of credit are expected when using the image.
If you'd rather specifically use the photos in your deck, or the slides from your deck, there are a few ways to do this:
1. First, make sure that if you're planning on selling the final product or using the photos commercially, that you use the iPad app (not the web app). In the Main Menu, under the gear in the bottom right, you can toggle commercial images only so that you don't end up using non-commercial photos. This feature's currently unavailable on the web, but we're working on adding it!
2. If you export your deck as a PowerPoint file and save the slides from PowerPoint or Keynote as images, the exported slides will include the Creative Commons licenses across the bottom. If you plan to crop, shrink, or alter the photos, however, we don't recommend using this method - instead, I'd use the third method listed below.
3. You can export your deck to PDF, where you will find a link to each individual photo in your deck on Flickr.com. Then you can download the images at full quality right from Flickr.com. Each image's specific license information will be visible on the right side of the photo. You can click each photo's license to get details on how to make sure you give proper attribution and use the photo legally.
For more information on how Haiku Deck uses Creative Commons-licensed photos, check out our blog post here.
Our support / tutorial article about free images and licensing might also be helpful.
You can also disable premium images in your iPad image search results with the steps in this article.