An Image Annotation Tool for Linux

Linux offers various image manipulation tools to help you edit images. Some of the popular ones include GIMP, Pinta, and Krita. However, while these tools offer tonnes of features and serve the needs of most users, many of them have a steep learning curve, and the added complexity in features makes them overkill for basic image editing and annotation needs.

For such use-cases, you rather need an annotation tool, like Annotator, which simplifies image manipulation and lets you annotate images with just a few clicks.

Follow along as we walk you through the steps to install and use Annotator on Linux.

What Is Annotator?

Annotator is a free and open-source image manipulation tool for Linux that lets you annotate your images with text, images, shapes, and other visual elements. It has a clean interface and is easy to use.

In addition, you can also use Annotator for cropping or resizing images and exporting them to various image formats.

Annotator Features

Annotator comes with a wide array of features. Here’s everything you can do with it on your machine:

  • Add text, shapes, stickers, and other callouts to highlight something important in an image
  • Blur out portions with sensitive information
  • Add magnifiers to zoom into details
  • Change the colors, line thickness, and font properties
  • Export images in multiple formats: JPEG, PNG, TIFF, BMP, PDF, and SVG

How to Install Annotator on Linux

Annotator is available on all major Linux distros. Here’s a breakdown of the instructions to install and get it running on your Linux machine.

On Ubuntu and its derivatives, you can install Annotator by running the following commands in the terminal:

sudo add-apt-repository ppa:ubuntuhandbook1/annotator
sudo apt update
sudo apt install com.github.phase1geo.annotator

On Arch Linux, you can download Annotator from the Arch User Repository as follows:

sudo yay -S annotator

If you’re using any other Linux distro, you can install Annotator via Flatpak. For this, first, make sure Flatpak is installed on your system by opening the terminal and running:


If this returns a version number, it means you have Flatpak on your system. Else, you don’t, and therefore, you need to install it first. Check out our Flatpak guide to learn how to install it on your Linux computer.

Once Flatpak is installed, use the following command to install Annotator:

flatpak install com.github.phase1geo.annotator

How to Use Annotator

To begin, start by launching the Annotator app on your computer. The easiest way to do this is to open the applications menu, search for Annotator, and run it.

Annotator will now present you with a welcome screen with two options: Open Image From File and Paste Image From Clipboard. Both of these are pretty self-explanatory, and you can pick one depending on your needs.

If you click on the former, it’ll require you to select an image file from your machine’s local storage on the following screen. On the other hand, clicking on the latter will automatically paste the copied image from your clipboard into Annotator.

In both cases, you’ll be taken to an edit window, with all the annotation and editing tools tiled on the taskbar.

We’ve listed the instructions to use these Annotator tools so you can familiarize yourself with them.

1. Add an Arrow

Most image manipulation tools, including Annotator, let you add arrows to your image to help you draw the viewer’s attention to something important.

Click on the Arrow button (the first button in the toolbar) to add an arrow to your image. Then, click and drag the arrow wherever you want on the image.

If you wish to change its size, tap on the arrow and drag it along its edges inward or outward. Similarly, to change its color, tap on it, click on the Shape Color button (third-last on the toolbar), and pick a color.

2. Add Shapes

In the same way as adding arrows, you can also use other shapes like rectangles, circles, lines, stars, etc., to add callouts to your images. To use them in Annotator, click on the Shapes button (next to the Arrow button) in the toolbar, and then tap on a shape from the available options.

Once you’ve added the shape, you can change its outline color, as you did with arrows. If you’ve used a filled shape, you can also change its color.

Similarly, there’s an option to add transparency to the shape too, which you can do by toggling the Add Transparency option in the Shape Color menu—kind of like a highlighter.

Lastly, Annotator also lets you change the border of these callout shapes. To do this, click on the Shape Border button in the toolbar, and from here, change the border width and the dash pattern as you like.

3. Add Text

Adding text is a useful technique to add important information or missing context to your images. In Annotator, you can add a text block by clicking on the Text button (with the letter a) to bring up all the text-related options and then entering your text in the window.

One neat feature of Annotator is the multiple text formatting options it offers. This lets you format text as a code block, subscript, superscript, bold, italic, strikethrough, or underline.

Furthermore, if you’d like to modify the font style, click on the Font Properties button (the last option in the toolbar). Here, you can search for your favorite font or click on the listed ones to set the font family.

Similarly, you can use the Size slider to adjust the size of the font. In both cases, Annotator will give you a preview of your changes in the tiny preview window at the bottom.

4. Magnify Important Details

Annotator also comes with a magnifier option, which lets you zoom in on small details in your image, so you can highlight it to its viewers.

If you’d like to use the magnifier, click on the Magnifier icon (with a plus sign). This will place the magnifier on your image. Click on the magnifier to move it over the detail you want to magnify.

Annotator also has a few more options for its Magnifier—three, to be precise—which are highlighted with tiny squares. Among these, the top one lets you control the amount of zoom, the middle allows you to change the magnification area, and the one at the bottom helps you change the size of the magnifier.

5. Blur Sensitive Details

For times when you’ve got some sensitive information in an image, blur comes through as a useful option to hide such things out.

Click on the Blur button in the toolbar to invoke the blur tool. After this, use the extensions along its edges to resize the blur area.

We think Annotator’s blur strength is fairly weak and would’ve liked a blur intensity adjuster on the tool.

6. Crop an Image

Cropping is a fairly common editing feature on most image manipulation tools. The cropping feature in Annotator lets you cut out unnecessary elements/parts of an image.

To use it, first, click on the Crop Image button to bring up the cropping tool. Then, use the extensions along the edges to select the area you want to crop and hit Enter to crop it.

7. Resize an Image

At times, you may want images in a particular size. Annotator has your back for such situations, thanks to its built-in image resizer, which lets you resize images with a custom size.

For using this resizer, click on the Resize Image button in the toolbar, and it’ll bring up the resizer window.

Here, enter your desired width and height for the image, and click on the Scale Proportionality button (with the padlock icon) to maintain the aspect ratio.

While you’re here, you can also set margins or change the unit from pixels to percentage. Once everything’s set, click on the Resize button to resize the image.

8. Export the Final Image

After you’ve modified your image, you’ll need to export and save it to your system locally. Annotator offers a bunch of export options to help you with the same.

To access these options, click on the Export Image button in the menu bar and select an option from the list.

Annotator will now ask you to give a name to this file and also choose the directory where you’d want to save it.

Perform these steps and hit Export to save the modified image.

All the Essential Annotation Features Under One Roof

If you’re someone who needs to edit or annotate a lot of images on your Linux machine, Annotator is probably one of the best image manipulation tools out there. It’s absolutely free to use, offers all the essential features you’d need, and is easy to use.

If you’re not a fan of standalone software, you can edit your images using the web browser with these free online image editing tools.

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