ImageGlass is a lightweight program and, therefore, does not consume much in terms of resources, even on my Windows 10 PC, e.g., it requires only between 10 and 30 MB of RAM in my average daily use. CPU usage is negligible. As an image viewer, ImageGlass meets all my requirements. It enables opening/viewing of all the image file formats I usually use, i.e., JPEG, TIFF, BMP. PNG, in a lightweight package. I can move from one image to the next easily, rotate clockwise or anti-clockwise, scale to width, height or fill, start a slideshow, etc. The user interface is very intuitive and user friendly, such that it did not take me long to learn how to use it effectively. Another feature I like about ImageGlass is the automatic update alerts - when an updated version of the program is available for download, I'm notified when I open the program. This feature helps me to have the latest version of the program installed on my PC, which in turn maximizes both performance and security. ImageGlass is customizable - you can select a theme pack (there are 23 to choose from at the time of writing this review), download it, and install it in the program to change the look and feel of the program. Although these theme packs don't alter the program's functionality in any way, I think it does improve the overall user experience.