NeeView is an open source image viewer that displays two images simultaneously like pages from a book
Most image viewer programs allow you to view one image at a time. I'm not talking about thumbnails, but a larger view of the pictures. If you want to browse your photo directories and view two images simultaneously, you should try NeeView.
It is an open source image viewer, and kind of resembles a web browser thanks to the navigation buttons and the address bar. The program's interface has a dark background, and there are two side-panels, one on either side of the window.
Drag and drop an image to start browsing the folder or, take the manual route from the File menu. Tap the right and left arrow keys to switch to other images in the folder. Interestingly, this also works with the right and left mouse buttons. The slider at the bottom of the screen provides another way to browse the folder, and the number next to it indicates the current and total number of images in the selected directory.
Want one more? Toggle the filmstrip mode from the view menu. F11 enables full screen mode, while F5 starts a Slideshow. Enable the topmost option to make the program to stay on top of other windows. Toggle dual page view using the Page menu or Ctrl +2, switch to normal view with Ctrl + 1
The "recent books" menu can be used to access the folders that you opened using the program. Speaking of which, the first option on the left side-bar, Bookshelf, also lists your recent media. This panel has its own address bar and buttons, click on the three-dot menu to change the view style (List, Content, Banner and Thumbnail).
The menu also lets you save playlists, set the search settings. Page List displays a list of all media in the current folder. The History section is yet another place where you can access your recent files from.
Moving to the other edge of the screen, the Information panel displays the image's properties and EXIF data.
The second option, Navigator, has some interesting tools. Rotate, scale, flip the images, select the stretch view. The fan shaped button opens the Effects panel that can be used to change the image's size, trim it, sharpen the image, toggle the grid. You can bookmark folders, and pagemark images and access them quickly.
To add various effects to your photos, click on its namesake menu and choose the effect you want to add. The available options include Blur, Embossed, Pixelate, Magnify, Bloom, Swirl, Monochrome, Ripple, etc.
NeeView can also be used to play videos. The Settings > Video section says that the application supports files that Windows Media Player supports including ASF, AVI, MKV, MOV, MP4 and WMV. I tried it with AVI and MP4 videos, and it had no trouble playing them.
When I tried playing an MKV h265 (x265) video, the program gave me an error. Oddly, it doesn't seem to support audio playback at all. On the bright side, you can use it to view PDFs, and many common image formats like JPG, PNG, GIF, BMP, etc. The program can also be used to view images that are stored in archives like 7Z, Zip, and comic book formats such as CBR, CBZ, etc.
NeeView is a surprisingly good photo viewer, with many useful and unique options. The only downside is that it has a slight learning-curve. The program is available in 32-bit and 64-bit versions, and also comes in a portable archive. Optionally, you can download it from the Microsoft Store. The official page is in Japanese, but the application's interface supports English. NeeView takes up about 25MB of storage space.