Better image viewing
Nick Peers goes hunting for a top-class image viewer – and is pleasantly surprised by what he finds.
Nick Peers goes hunting for a top-class image viewer and editor, and is pleasantly surprised by what he finds.
Are you looking for a good tool to view – and perhaps edit – your images easily? While
Shotwell might seem like an obvious choice, it’s more geared towards building a library of images rather than acting as a quick-and-easy image viewer. What you need is nomacs.
The tool bills itself as an “image viewer”, but that does it a major disservice. It’s an excellent choice for viewing single files, or the contents of folders, supporting a wide range of image formats (including
Photoshop PSD and RAW image files from digital cameras), but it does so much more. You can edit a photo’s metadata for example, and correct problems with photos courtesy of nomacs’ Adjustments menu. It even throws in a few clever effects, including photo mosaic and tiny planet tools. All in all, it’s an excellent tool to add to your image-editing arsenal. As always, nomacs is available through Ubuntu’s universal repos (and therefore the Software Centre), but you’re tied to an older version. For example, Ubuntu 20.04 users would be stuck with version 3.12. A better bet is to install it through flathub – assuming you have
flatpak installed, simply issue the following command:
$ flatpak install flathub org.nomacs.ImageLounge
Press Y twice when prompted and wait for nomacs to install all its required dependencies. Once complete,
nomacs can be launched via the Gnome launcher. On your first run you’ll be prompted to select a language – only English is available, so simply click OK to find yourself at the main nomacs screen.
Tool with a view
You can view a single image or load in a folder full of images, which can be displayed as a slideshow or viewed one at a time with the help of an optional Thumbnails panel. But that’s not all: nomacs can also load the images inside a compressed folder, and display all the images inside a Microsoft Office document (such as embedded graphics in Word or PowerPoint) too.
To select your first image or folder, open the File menu and choose Open for a single file (including compressed and Office files), or Open Directory to load the contents of an entire folder.
When you open a single file, it’ll be displayed within the nomacs window. If you open a folder then a new view – Thumbnail Preview – is opened, displaying the images as a series of cropped square previews. The view is rather basic and not very helpful, but one of nomacs’ strengths is its customisability. More on that shortly. For now, double-click an image to open it and then use the arrow keys (left and right) to cycle through the photos in the folder.
The same technique applies when viewing the images in a compressed or Office file. When opening these, the first image in the list is displayed, and you can cycle through them using the arrow keys. This can quickly become tiresome, so it’s time to start tailoring the nomacs user interface using its customisable panels.
Start by pressing the T button, which adds a panel of thumbnail images from the currently selected folder. By
default, it floats on top of the image pane. To reposition it, right-click any of the images and choose Show Left or wherever you’d like to float. Choose Undock, and with some effort you can incorporate it with the other floating panels, although it’s quite fiddly (if you end up with a blank window at any point, just press Alt+F4 to close it).
Build a perfect view
You can access further user interface add-ons via the Panels menu, where you’ll find no fewer than 15 different panel types are available. The annotation (below left) reveals six of the most useful. Those listed above the divider can be moved around the user interface as required, while those below are static semi-translucent panels that ‘float’ above the image itself. All panels can be quickly shown or hidden as required by pressing F.
Panels that ‘attach’ themselves to the edges of the main screen can be made to float, then dragged into position elsewhere as required. Click the button to the left of the close button for that panel next to its title and it’ll convert into a floating box. Once done, click and drag this into its new position to snap it into place. Panels can also be grouped together along each side – either next to each other (drag one panel to the edge of another) or grouped into tabs (drag one panel on top of the other). While only one is visible at once, you free up more space to display your main image.
Once positioned, look for a drag handle dividing each panel, which you can use to resize the panels in relation to each other. Some panels – including File Explorer – can further be customised by right-clicking inside the panel and exploring the options shown, while others like the Thumbnail Preview display additional options via a toolbar. In the case of Thumbnail Previews, you can adjust the size, switch between cropped square previews and regular ones, and choose to display the file name beneath each thumbnail to make each one easier to identify.
Creating slideshows
When viewing multiple images at once, you should see a series of slideshow buttons at the bottom of the screen (linked to the Player panel). Pressing the Play button (or hitting the Space key) will immediately start a slideshow with a three-second delay between pictures. Choose Edit>Settings>Display to locate tools for customising your slideshow. You can change the time between pictures, and tweak the transition effect.
When opening the Settings tool you’ll notice nomacs opens it in its own tab. The tool supports multi-tabbed viewing of images too, which means you can browse multiple folders at once, or open the same image in two separate tabs and experiment with different edits on each, switching between the tabs to compare your changes. In fact, nomacs offers a more elegant means of comparing images and changes side-by-side, as revealed in the ‘The benefits of sync’ box (page 65).
If you’re happy to stick with tabs, press Ctrl+T (or choose View>New Tab) to open new tab. You’ll see a list of recently opened images/folders – click one to reopen it, or open a new file or directory in the usual way. When you set up multiple tabs, nomacs will offer to save those tabs when you quit the program – this enables you to build your own workspace with permanent access to frequently accessed folders or photos.
Editing images
Although nomacs bills itself as an image viewer, that does it a huge disservice. The program features a suite of useful editing tools, most of which are available under the Adjustments menu. These are supported by multiple undo and redo, and a handy Edit History panel that enables you to review and quickly jump back to any point in your editing.
While nomacs can’t hold a candle to the likes of GIMP, its tools are still handy for when you’re browsing your many images and spy an opportunity to tweak some minor issues. Start with handy Crop and Resize tools, both also accessible from nomacs’ Edit toolbar. After selecting Crop, a guide tool appears as you click and drag, complete with a rule-of-thirds grid for helping better frame photos. Not only can you resize the Selection tool, you can rotate it too. You’ll be able to set an aspect ratio for your Selection tool, plus replace the rule-of-thirds grid with a regular grid (or none at all).
Resizing your image opens a new dialog with all the tools you’d expect to change its size and resolution, plus resampling options, optional gamma correction and a handy preview you can pan and zoom into.
Make further adjustments
The first five options under Adjustments – Grayscale, Auto Adjust, Normalize Image, Invert Image, and Flip Horizontal/Vertical – are all simple one-click options and self-explanatory. The following nine options – ranging from Rotate through to Sharpen – open their own Edit Image panel. Its appearance is a little incongruous compared to the other panels, but contains a series of context-sensitive sliders enabling you to fine-tune the effect in question.
As you adjust the slider, the changes can be seen on the image – these can be undone using the buttons at the bottom of the panel. Note, changes aren’t written to disk until you save them.
You can save your changes via the File menu, where you’ll see various options: choose Save as if you want to save in different supported format (PNG, JPEG, TIFF, BMP, Portable Pixmap, X11 – bitmap and pixmap, Wireless Bitmap or WebP), and Save A Copy to create a duplicate in the same format (simply rename it before clicking Save). The Save for Web option makes it possible for you to save the file in JPEG format at a specific resolution: 800x600, 1,024x786, 1,920x1,080 or the original size. You’ll also be prompted to save your changes if you try switching to a different photo within the same folder.
One tool stands out from all the others: Tiny Planet. It seems a little out of place with all the other
adjustments because this is an effect rather than an edit. It’s designed to work with 360-degree panoramic photos, which you can capture using your Android phone’s camera app. Once created, transfer the photo to your PC, then load it into nomacs before choosing Adjustments>Tiny Planet and using the controls to adjust its size and orientation.
Extra features
In addition to nomacs’ editing tools, there are two other areas where you’ll find a host of extra features. The first can be found by opening nomacs’ Tools menu where you’ll find six handy utilities covering a range of uses. The first two are designed to extract all the images from a single file, namely multi-page TIFFs and compressed files. For the former, choose Tools>Export Multipage TIFF to select the file in question, then choose where to save it, what filename to give it and – in the case of a multi-page TIFF – which page(s) to extract.
The second option – Extract From Archive – covers both zip files and compatible Office (docx, xlsx and pptx) files. After selecting your file, you can either accept the default save location (a newly created sub-folder in the same location as the original file) or choose your own. You’ll see a full list of images within the file, but you’re unable to pick and choose which images to extract. Tick Remove Subfolders to aggregate the files into a single folder (this is recommended when stripping files from Office docs).
Produce a photo mosaic
Mosaic Image enables you to produce a photographic mosaic – define your source image, then pick a folder containing all the images you’d like to use to generate the mosaic effect. Once done, choose how many ‘patches’ or tiles you want, and set a size for your final image, then click Generate and wait for nomacs to select appropriate images to create your effect. Once done, expand the Create Mosaic Image dialog to increase the size of the preview, then use the Darken, Lighten and Saturation sliders to adjust the effect.
The batch-processing tool is a real time-saver: if you want to apply the same edits – from resizing, cropping or converting to a different format to performing one or more of nomacs’ adjustment filters – to a group of photos, don’t manually perform the same actions on each. Instead, follow the step-by-step guide to use the batch-processing tool, which not only speeds things up
but ensures the same consistency is applied to all your selected images.
The Compute Thumbnails option comes into play when viewing a folder of images, either with or without the Thumbnail Preview pane. Selecting this will prompt you to create thumbnails for all the images in that folder – with an option to overwrite any existing ones if required.
The final tool is ‘Add Image Format’. If you find an image that nomacs can’t open, it’s probably only because the file extension hasn’t been added to its filter. Click Browse to select the file and – if nomacs informs you that the format is supported – click Add to add the extension to the supported list (to see which extensions are already supported, go to Edit>Settings>File Associations).