The Photos app on Windows 10 PCs and mobile has been a point of some contention. It's been a work-in-progress for sure, and a number of features have been requested to turn the app into something a little more competitive with the default apps on other platforms. Microsoft pushed out an update to the app that resolves a few outstanding issues, include the addition of a simple slideshow feature.
The update to version 16.703.10032.0 brings the aforementioned slideshow feature, which is a relatively simple option at this point. Hit the slideshow button, and your images will cycle through without any UI or available options. Tap the image currently being displayed and you're simply returned to the list.
The other addition (via Windows Central) is a transition when selecting images to view. Rather than jumping to an image, there's now a smoother fly-in transition that makes the entire process a bit more comfortable. It's not a huge addition, but it's one of those things that makes a smartphone feel more elegant.
You should receive the update if you're a Windows Insider. Let us know in the comments what you think of this new functionality.