This tutorial shows how to remove background in a jpg image using GIMP-GNU Image Manipulation Program. GIMP can be found in any Linux distribution including Ubuntu desktop and Slackware Linux. To open GIMP in Ubuntu desktop, click Applications - Graphics - GIMP Image Editor. Here is an example of how GIMP looks like:

You can use Gimp menu File - Open to open the jpg file that you want to remove the background. See the example screen shot below:

Browse and select the jpg image from the directory in your computer. Select the jpg file and click Open. See the example screen shot below:

Here is the jpg image example. We are going to remove the white color background and make the image transparency.

To remove the background color from the image, click Layer menu and choose Transparency. In the Transparency menu, choose Color to Alpha. See the example screenshot below:

You can see the result below. The white background color has been removed from the jpg image.

Now we need to save the image (you can edit the image later if you want). Click the Gimp File menu and choose Save As.... See example screen shot below:

Name the image as filename.png. We must change the '.jpg' extension to '.png' extension. Change the location to where you want to store the new image.

When you click Save, a new pane pops up. Click 'Save' again and you are done.

That's all.