If you are not happy with the Photos app that comes pre-installed with Windows 10, then you can switch to a number of third-party image viewer programs like FastStone Image Viewer. Not only it supports a large number of image file formats but it is also very fast in handling even the largest of the images. Moreover, it offers a great many tools for editing or retouching of the images which is unusual for image viewers.
FastStone Image Viewer is available in two formats – as an installer package and also as a portable program. The portable program is great for using on any Windows PC without having to install anything on that computer. But if it is your own computer, then you it is recommended that you install FastStone Image Viewer for full set of features.
With so many features, FastStone Image Viewer is not just an image viewer but it is a pack of many different tools such as image editor, image file format converter, image browser and of course the image viewer. It uses an intuitive full screen interface where the images are displayed fullsceen but various options appear only when you drag the mouse pointer near the edges of your screen – it displays information about image file near the right, a strip of images near the top edge, various tools near the left edge, and the file toolbar near the bottom edge of your screen.
Unlike some other image viewer software, FastStone Image Viewer supports not only various image formats (BMP, JPEG, JPEG 2000, animated GIF, PNG, PCX, PSD, EPS, TIFF, WMF, ICO and TGA) and popular digital camera RAW formats (CRW, CR2, NEF, PEF, RAF, MRW, ORF, SRF, ARW, SR2, RW2 and DNG) but it also supports some of the video file formats. Furthermore, it can also import pictures directly from your digital camera in the RAW formats and save them to your hard drive.
You can download FastStone Image Viewer from http://www.faststone.org/FSViewerDetail.htm.
This is a fantastic and powerful alternative to the Photos app. Also, I appreciate the option of the windowed view (View > Layout > Windowed View) which gives an experience similar to that of the Photos app.