nomacs is a versatile multimedia application designed primarily for image viewing and editing on Windows. It features semi-transparent widgets that provide useful information such as thumbnails, metadata, and histograms. Users can browse images within zip or MS Office files, with options to extract them into a directory. The program also allows for the display of metadata and the addition of notes to images. A thumbnail preview of the current folder and a file explorer panel facilitate easy navigation between directories. Additionally, users can apply file filters to display images based on specific criteria, enhancing the browsing experience.

Beyond simple viewing, nomacs offers a range of image manipulation tools to adjust brightness, contrast, saturation, hue, gamma, and exposure. It includes a pseudo color function for creating false color images. A standout feature is its ability to synchronize multiple instances, enabling users to compare images side by side by zooming or panning in unison. Licensed under the GNU General Public License v3, nomacs is free for both private and commercial use across various platforms.