Overview Panel (Zooming)

The Overview Panel (Menu > Panels > Overview) enhances zoom and pan. The blue rectangle shows the current viewing area. You can pan to a specific location by dragging this rectangle to the desired position. The scrollbar at the bottom allows you to zoom. If you want to zoom to a desired factor (e.g. 600 %) you can mark and replace the text accordingly.

Overview Panel
Overview Panel

GSoC 2015

nomacs was not accepted for GSoC 2015. We would like to thank all students who were willing to contribute to nomacs. But don’t forget, it’s open source – so you are always welcome to contribute : )

– the nomacs team

But which image format should I take?

Since we see a lot of people choosing the wrong image formats on a daily basis, we have created a short cheat sheet for you. Though JPEG is probably the easiest way to archive your pictures, there are several incentives to choose another image format depending on the image content or purpose. (You can also download the cheat sheet)

Image formats for photos
Image formats for photos
Image formats for illustrations
Image formats for illustrations

– the nomacs team

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