Took a bunch of photos and want to make them into a slideshow instead of a static collage? Then you should check out PicFlow from Red Cactus. The slideshow maker is easy to use and doesn't require you to sign up for a service just to add some flair to your photos.
PicFlow walks you through the slideshow creation process, prompting you first to add photos from your Camera Roll to the slideshow. Once the photos are imported, you can tap and drag them into their proper order. You also can pinch to crop the photos and adjust what section of the image is displayed in the resulting video. There are no other editing options, so you will need to use an image editor like Aviary to tweak the contrast and adjust the color before you import them into PicFlow.
Once the photos are "just right," you can add music from your iTunes library to the slideshow. The song has to be stored on your device and not stored in iCloud for you to import it. The app then allows you to pick the part of the song you want, so you are not stuck with only the first 20-seconds of the clip.
In the third and final step, you can adjust the length of the video, which is set to 15 seconds by default in order to meet the video upload requirements of Instagram. You also can record the photo transition timings by tapping, allowing you to sync your photos to the beat of the music.
When you are done with the music part, you are ready to preview the clip and then share it. Tapping on the "Share" button allows you to export the clip to Instagram, Facebook, YouTube or your Camera Roll as a video. If you want to fix something before you compile the clip, you can easily jump back through the steps and make changes.
PicFlow includes a watermark and ships with a default cross-fade transition. If you want to use other transitions or remove the watermark, you can unlock those features via an in-app purchase. In-app purchases are reasonably priced, ranging from 99-cents to remove watermarks and going up to US$2.99 to unlock the entire app.
PicFlow is available for free from the iOS App Store. It is compatible with the iPhone and requires iOS 7.