Windows 10

We have tested nomacs on windows 10. Everything works out as expected, except that the Frameless View seems to be obsolete since Microsoft removed the window frames.

— the nomacs team

nomacs running on windows 10
nomacs running on windows 10


Want to Support nomacs?

we would need your help for increasing the support of nomacs on different OS:

  • OSX Build in addition to Petr’s MacPort packages we would love to distribute dmgs of nomacs.
  • Linux Plugins we are seeking for someone who can help us with the packaging of plugins for Linux.

If you have experience in any of these fields and want to support us, you can leave a reply to this post or write us an e-mail (

– the nomacs team


With the synchronization it is possible that multiple viewers perform the same action (like panning, zooming, etc.). This feature is useful when comparing two images.

Synchronization on the same computer

For synchronization on the same computer at least two instances of nomacs have to run. Via the “Sync”-Menu it is possible to connect to all viewers or a specific viewer can be chosen by selecting the image title of this viewer. Additionally it is possible to connect two viewers by keeping the CTRL and ALT key pressed and drag from the image of one viewer to the other. For actions which should be performed on all connected instances the ALT key has to be kept pressed (e.g. hold the ALT key pressed and use the mouse wheel for zooming on all connected viewers).

Possible actions which can be performed:

  • Panning ALT+mouse
  • Zooming ALT+mouse
  • load next/previous File (ALT+right resp. ALT+left)
  • synchronize zoom level and position in the image with CTRL+D
  • overlay the two images and change the opacity of one image with CTRL+TAB
  • arrange synchronized viewers with CTRL+SHIFT+TAB

Synchronization in the local network (LAN)

First you have to enable “network sync” in the network preferences of nomacs on all computers  you want to use. To synchronize viewers via the local network one nomacs has to start the server using the menu. The viewer on the other computer can then connect to the server.  Additional to the actions on the same computer (see above) images can also be sent over the network by pressing ALT+I (or using the menu:  Sync -> Send Image).

In the settings dialog actions can be forbidden for all clients (see Settings-Network). So you can forbid a client e.g. to zoom into your image and/or to send you new images.

Note: If a server connects to another server in the network, all clients of this server disconnect and establish a new connection to the target server. Also the server of the current viewer is stopped.

Touch & Gesture Support

The touch support was extended in nomacs 2.2. The illustration below shows the most important gestures. Horizontal swipes move to the previous/next image if the image fits into the window (otherwise, these gestures are used for panning). Swiping down from the top opens the thumbnail panel while an upward swipe from the bottom displays the metadata. Plus you can zoom using pinch gestures.

mouse and touch gestures
mouse and touch gestures

Nomacs & Archives

nomacs supports zipped archives since version 2.2. Hence you can simply drop a zip archive to nomacs and then browse all images in the archive. Fair enough, but the really cool feature, is that you can browse through all images of Microsoft Office documents by simply dropping the files to nomacs. In addition, we have added a tool (Tools > Extract From Archive) which allows to extract all images from Archives to a folder.

Adding new file formats

Since the last release we are getting more and more requests if we can support different file formats. Apparently it turned out, that we already support most of them but we have not added the file extension to our file filter. This is especially true for RAW formats of image files, we just simple don’t know all extensions of all manufacturers and we don’t have sample images from all of them for testing.

But there is a simple solution: you can easily try to add new files formats to nomacs. You just have to use File -> Add Image Format – this opens a dialog where you can drop (or load) your images and nomacs will tell you if the file extension is supported. If it is supported it will display the image. After adding the file format you can use our File Filter settings in the preferences dialog to set nomacs as default viewer for these images. If you have successfully added a new file format, please drop us a note in our bug tracker and we will add the extension to nomacs. If nomacs is unable to load you file format, please add a new feature request. If possible attach also the image to the request so we can test it easily.

— the nomacs team

2.0.2 supports .vec file

In 2.0.2 (we just noticed that we are now the half of not found : )  a new feature was introduced which is very useful for us and we think it may be useful for those of you who also work in the computer vision field. We are now able to load the .vec file of the OpenCV Cascade Classifier. So you can easily control if the patches you trained, or the patches OpenCV created automatically are correct. Of course we have not added the .vec extension to the default settings of nomacs, because there exists a lot of other vec files. Thus, you have to add the extension to nomacs manually. You can do this by opening the “File” -> “Add Image Format”  dialog. Then you can drag&drop your file into the dialog or use the browse to the file.

add-formatsAfter clicking add you have to name the new file format. After that you can open your .vec files with nomacs.img-2014-07-31 09.22.22Due to some limitations of the fileformat nomacs assumes that the patches are square and thus if you open a file containing non-square nomacs is unable to load it. If you want to use non-square patches you have to specify the size in the file name. You can do this by adding “-w[width]-h[height]”. So for example you have to name your file “samples-w35-h25.vec”. Have fun with this feature and may it simplify your training step

— the nomacs team