gThumb Image Organizer Basics

  • The JPEG file of a photograph contains more information than just what is necessary to show the picture. It also contains a lot of text information called EXIF (Exchangeable Image File Format) data. Most of this is technical photographic information set automatically by the camera and includes the make and model of the camera, the f settings, the shutter speed, and so on. It is of little or no use in organizing and finding pictures. But there are a few fields, left blank by the camera, which can be used to label and index the picture. These fields can then be searched to find pictures of a particular subject or taken in a particular place or at a particular time.
  • gThumb is a program produced by the Free Software Foundation, Inc. to edit this EXIF information, to enter into it a title, a date, a discription and location of a picture as well as various tags with names made up by the user. It can also search a directory for pictures with a desired word or words in the title, a desired date, location, or tag. It also has some capability for image editing, such as cropping, rotating, brightness and contrast adjustment, and red-eye elimination, but that is not its strong point.
  • Its strong points are clarity and simplicity in editing the metadata data and power in logical search queries to find the pictures you want. It is available free for Linux but not at all for Windows or Mac. It is easily gotten from the Ubuntu repository. On Linux, it competes with Shotwell, and F-spot. In the world of free software for Windows, IrfanView and Google's Picasa also work with with the EXIF data, and data that has been entered by any one of them can be used by all of the others; it is embedded in the .jpg file and moves with that file wherever it may go and is available under any operating system to any program that works with the EXIF data. Picasa is also available for Mac and has a convenient way of “geotaging” a picture with longitude and latitude by working with GoogleEarth or Google maps. While this is formidable competition, for ease of editing and power of searching, gThumb heads the list.

  • As of April 2015, the help obtained by clicking Help on the main menue does not match the program. The following information matches the program installed from the Ubuntu repository in late March 2015. The "About" page says that it is version 3.2.7.

Opening gThumb

  • To get started with with gThumb, put a number of .jpg files that you want to organize into a directory. gThumb must be opened in a way that is not conventional. If you just start the program and then click the File menu item in hopes of being able to navigate to your directory, you will be disappointed. The closest thing you will find is “Import”. If you click it and move to your directoy, and choose to import its contents, gThumb will copy all the files in your selected directory into the Pictures directory. Chances are, that is not at all what you want to do.
  • So how do you open gThumb to work on the .jpg images where they are? In Ubuntu, click on Files in the Ubuntu Launcher. Navigate to your directory; the screen will fill with thumbnails of your images. Right click on any one of them. A menu drops down. Choose “Open with ...”. You should see gThumb in the list; click it. A window opens with your picture occupying most of the screen. Across the top, however, is an all-important tool bar. There are six square, white zoom buttons; you can try them to see what they do. The button of immediate interest, however, is the square on at the far left made up of four small white squares. Click it. The screen fills with thumbnails, and we are ready to start work with gThumb.
  • The next time you go through this process you can speed it up slightly for the future. At the point where you right click an image and a menu drops down, click the bottom item, Properties. Click the “Open With” tab. Click gThumb in the list of “Recommended Applications” and click “Set as Default” and then click “Close”. The next time you go through the process, when you start the process by right-clicking an image and a menu drops down, “Open with gThumb” will be at the top of the list and you just click it to get started.

Editing the Metadata

  • To get started with with gThumb, put a number of .jpg files that you want to organize into a directory (also called a folder). Open gThumb and in the opening window navigate to your directory. Thumbnails should soon fill the gThumb window. Click on the thumbnail of a file whose EXIF you want to edit. Then in gThumb's main menu across the top, Click Edit and then Comment. gThumb also has a tool below the main menu; equivalently, you can click “Comment” in it. (“Comment” apparently is intended to mean the part of the EXIF data that you are likely to want to change.) The window shown below appears, without, of course, the data that has been entered about the Royal Palace at Knossos.


  • Fill in the Title, Place and Date fields as appropriate. You will later be able to search for what is in these fields and to show them below the image in the browser view. We will return to the Tags field. Information can also be recorded in the large Description box. This information can be searched but cannot be displayed below the image in the browser view. In the previous picture, you perhaps noticed that there was a tab with the label Other. Clicking it brings up the window shown below. It has places for location information which will not be confused with geotags. However, it does not seem to be possible to search for information on this tab, so it cannot be used for indexing, at least not in gThumb.


  • We return to the General tab and the Tags box. Tags are one-word labels we can give to pictures. They can then be used to search and locate pictures with a particular tag. Note the drop-arrow to the right of the Tab field. Click it, and you will see a rather strange initial list of possible tags. Perhaps someone was using them, but you will probably want to delete most of them by right-clicking on them and choosing “Delete”. Then by clicking in the box on the top, you can type in new tags to your liking. As you do so, your tag is added to the list of available tags. Next time you want it, you just have to click on it.

Showing the Metadata with the Thumbnails

  • gThumb's browser window showing the thumbnails does not automatically show any of the metadata that goes with the images, not even the filename of the image. That can be remedied to show selected metadata that was on the General tab when editing the EXIF data. To do so, click Edit on the gThumb main menu and then Preferences and then the Browser tab, so Edit > Preferences > Browser. A window comes up as shown below.


A click in the box of an item moves it into the top pane of the window, where it appears with its box checked. Items in this top pane can be dragged up or down; they will appear in the browser in the order in which they appear in this top pane. Here is the window after selection of the items to show.


Finding the Pictures You Want

  • Once again, start from Edit but then pick Find. A window appears like that below The one shown, however, has been expanded by the clicking the big green + control on the right to add a second criterion and the “Match” control has been set to show images which match either of the criteria specified below.


  • The result of the search – which took several seconds in a directory with about 1000 jpg's – was to show the two images which matched one or the other of the rules, as shown below.


Image Enhancement

  • When an image is selected there appear at the far right end of the toolbar two rather circular icons. The rightmost one, resembling a cogwheel, shows technical EXIF data. The one just to the left of it, depicting a painter's palette, offers some image enhancement tools. They include cropping, rotation, automatic adjustment of brightness and contrast, adjustment of colors, equalization, horizontal and vertical flip, resizing of the photo, and red-eye correction.

gThumb (last edited 2015-04-07 04:53:40 by almon)