GThumb is an image collection manager. It shows a directory structure in a panel at the left of the screen, and when you select a folder from that panel which contains bitmapped graphics, these are displayed in the main panel. Right-clicking or double-clicking will open a full screen view of an image similar to that in the Image Viewer, while thumbnails for the remaining images are displayed along the bottom of the screen. You can return to the Browser view through pressing Escape, using the View menu, or clicking the first button on the toolbar at the top of the display.
GThumb can be used to import images from an external device like a camera or scanner, and to export images to other locations, including Web-based image hosting sites like Facebook, Flickr and Photobucket. An option under the Edit menu allows you to look for and mark duplicate images for deletion. Edit/Preferences controls the way that GThumb looks and behaves by default. It includes a large number of Extensions – i.e. plugins – which add capabilities to the program.
Figure 24: GThumb
The View menu in GThumb allows you to run a slideshow and to change the sort order in which images appear. The Bookmarks menu allows you to select particular locations on your system. These will then appear at the bottom of the Bookmarks menu the next time it is opened.
GThumb has three ways of organising image files: through filters, categories and tags.
A Filter is a temporary criterion which hides images you don’t want to see at that moment. You can identify a field on which to filter the images by clicking on Edit/Filter and turning on the checkbox for the field or fields you want to use. Make sure that ‘Filterbar’ is turned on in the View menu, and you will see a drop-down box saying ‘all’ at the bottom of the screen. Click on this to access the field you want to filter on, and supply a value: e.g. ‘Filename contains dog’. You should then only see the matching images in the browse display. To restore the complete list, select ‘All’ again.
A Catalog is a ‘box’ or ‘album’ in which to put images – e.g. ‘Cousin Fred’, ‘Spanish Holiday’. Each image can be assigned to one Catalog only. To assign catalogs, select one or more images and right-click. You can assign an existing catalog or create a new one. Alternatively, click on ‘Organize’ at the top right of the screen, and Gthumb will attempt to categorize your images automatically based on the date on which they were taken. Unfortunately Gthumb doesn’t appear to offer any way to use these Catalogs once you have assigned them.
Tags are short words or phrases describing the image: ‘Safari trip’, ‘Brian and Judy’, etc. One image can have many tags, and one tag can be used on many images. They can be assigned by right-clicking in the same way as Categories. To create a new tag, just type it in at the top of the Tags dialog box and Save. But once again, there doesn’t seem to be any way to use tags to find or filter images, which makes them pretty redundant.