nomacs is a free, open source image viewer, which
supports multiple platforms. You can use it for viewing all common
image formats including RAW and psd images.
nomacs features semi-transparent widgets that display
additional information such as thumbnails, metadata or histogram. It is
able to browse images in zip or MS Office files which can be extracted
to a directory. Metadata stored with the image can be displayed and you
can add notes to images. A thumbnail preview of the current folder is
included as well as a file explorer panel which allows switching
between folders. Within a directory you can apply a file filter, so
that only images are displayed whose filenames have a certain string or
match a regular expression. Activating the cache allows for instantly
switching between images.
nomacs includes image manipulation methods for adjusting brightness,
contrast, saturation, hue, gamma, exposure. It has a pseudo color
function which allows creating false color images. A unique feature of
nomacs is the synchronization of multiple instances. With this feature
you can easily compare images by zooming and/or panning at the exactly
same position or even by overlaying them with different opacity.
nomacs is licensed under the GNU General Public License v3 and
available for Windows, Linux, FreeBSD, Mac, and OS/2. It is free
for private and commercial use.