How to use GIMP

Give your photos a professional finish

Choosing a photo editor usually means making a difficult decision: do you want a free program, or do you want a powerful one? With GIMP (the GNU Image Manipulation Program) you can have the best of both worlds – it's as powerful as many professional image editing programs, and because it's open source, it's completely free to download and use.

Getting started with any program that can be compared to Photoshop is potentially daunting, and GIMP has a slightly unusual interface, but once you're familiar with its most powerful tools you'll have no trouble making your photos look amazing.

GIMP for Windows is available to download from TechRadar, and the Mac and Linux versions can be found on the developer's site

1. Download and install GIMP

First, download GIMP – the Windows version is available from us here at TechRadar, and versions for Mac and Linux can be found on the developer's site. GIMP is a large program, so be prepared for the download to take some time, particularly if your internet connection is a bit sluggish.

GIMP's default configuration is a set of floating windows, but it was recently upgraded with an optional single-window view

2. Adjust the layout

You can accept all of the default options and zip through the installation in a matter of moments, then click Finish and then launch the program for the first time. The first launch may take slightly longer than you expect as the program spends a little while analyzing your PC and searching your hard drive.

When GIMP is up and running, you'll immediately see that it looks a little different to most other software, thanks largely to the fact that it started life on Linux. The interface is made up of multiple windows, and these can be rearranged however you want to suit the way you work – or you can click Windows > Single-window Mode for a more familiar environment.

Rather than simple presets, GIMP gives you total control over the colors in your photos

3. Fine-tune colors

It's possible to use the GIMP to create digital paintings from scratch – it has a wide and versatile set of tools for creating original artwork – but it's more likely that you'll want to use it as an image editor to touch up and optimize photos

Open an image, then explore the range of editing using the tools in the Colors menu. There are no automated optimization tools as you may find in other less powerful image editors. Instead, GIMP has a powerful set of options such as colour adjustment, saturation and contrast balancing, as well as more advanced curve adjustment.

GIMP's excellent healing tool lets you 'paint' out blemishes, scratches and distracting objects in photos

4. Paint out flaws

GIMP's healing tool is extremely useful for photographers. It looks like a sticky plaster in the left-hand toolbox, and can be used to remove all manner of unwanted elements from images, such as spots and blemishes on faces, rogue pieces of foliage, and anything else you'd rather eliminate.

Here we've used it to remove branches from the corner of the image. Zooming in is helpful here – just tap the + and - keys to adjust the magnification.

With the Healing tool selected, hold Ctrl and click an area of the image that could be used to mask an unwanted area. You can then draw over the element you wish to remove holding down the left mouse button, and it will be magically wiped out.

GIMP contains an excellent collection of photo-enhancing filters, including many creative options

5. Apply filters

One of the quickest and easiest ways to improve the appearance of just about any image is to make use of the many filters that are built into GIMP. Under the Filters menu you'll find everything from the option to add a lens flare effect to your images, to making it look as though your image has been printed on canvas.

Don't be afraid to experiment here – you can use the Undo option if you don’t like how something turns out.

It's also worth noting that you can apply an effect to a section of an image rather than the whole thing by making a selection before applying a filter.

You can adjust the amount of RAM allocated to GIMP's Undo tool, enabling you to undo more functions

6. Set memory allowance

If you start to do a great deal of experimentation you might find that you start to run out of undo levels. To help overcome this problem, you can tweak program settings so that more memory is set aside for undoing actions. Click the Edit menu and select Properties, and in the Environment section you can choose either the number of levels of undo (the number of actions you will be able to reverse), or the amount of undo memory.

While you're in Preferences, it's worth checking to see if there are any other customizations you want to make.

GIMP's transformations tool enables you to correct issues with perspective in photos, or correct skewed lines

7. Apply transformations

Another powerful option found within GIMP is the transformation tool. You'll find the full range of transformation options in the Tools menu, and some of them can be accessed from the left-hand toolbar as well.

If you have taken a photograph and you would like to slightly adjust the perspective in order to straighten things up a little, the Perspective tool is great. With the tool selected, you can drag and twist your image from the corners, previewing how things look on the Perspective Grid. When you're happy with the results, click Transform.

GIMP is the work of a community of volunteers, many of whom have created guides to help you get more from the software

8. Export images and find more info

When you've finished, you should opt to export the result rather than saving it unless you intent to return to GIMP and edit it again later. GIMP saves files in its own proprietary format, which keeps all their layers intact, but can't be opened in other programs.

If you click File > Export instead, you can select more common formats such as JPG and PNG.

As with any photo editor, just how far you take things with the GIMP is entirely up to you. If you're looking for more guides about what you can do with the program, take a look at some of the official online tutorials.