The latest update (Windows 10 Mobile Insider Preview Build 10536) for the Windows Insiders have brought in a new updated Photos App for the Windows 10 Phone users. This update introduces a folder view that makes it easy for you to see your OneDrive and PC folders in the Photos app. On your phone, you can also see folders on your SD card.
This update also brings faster photo viewing and context menus. Specifically, for phones, zoom and panning is faster, and you now have an option to mark an image as a favourite. This update is not available for PCs at this moment; an update will be rolled out soon.
Microsoft had introduced one-handed mode for larger phones sometime ago. In this build, they have also enabled the ability to use one-handed mode on all Windows phones.
This can be enabled by pressing and holding the Start button. When you do this, your screen will slide down so you can reach items at the top of your screen. To slide the screen back up, tap the black space at the top of the screen, or press and hold the Start button again. One-handed use will also naturally time out after several seconds and return to your regular view