In-class exercises to accompany the Image Editing for Beginners workshop that I teach. Provides step-by-step instructions to help you accomplish some simple editing using Gimp (the GNU Image Manipulation Protocol).

1. Image Editing for Beginners
Teresa Beary (May 2013)
You’re welcome to use your own images for these exercises, or some example images have been
provided with the class materials.
Please copy this folder to your personal drive so everyone has access to the originals.
Exercise 2 – Adding a transparent background
1) Open one of the “clipart” images using Gimp.
2) Add an alpha channel to the JPG image. (Do A or B.)
A. In the Layers dialog box, right-click on “Background” and select “Add Alpha Channel”.
B. On the Canvas window, select Layer > Transparency > Add Alpha Channel
3) Use the magic wand selection tool to click on the white part of the image.
4) Press Delete on your keyboard, or go to Edit > Clear.
5) Use the Erase tool to remove any lingering background.
6) Go to File > Save as > name your file and end the name with “.png”
7) Open up your image (maybe drop it into PowerPoint) to verify that you successfully made it transparent.
1) Open PowerPoint and create a SmartArt or other graph/chart/diagram.
2) Go to File > Save as… > Change the Save as file type to “PNG Portable Network Graphics Format”.
3) Save the current slide only.
Does your image need to be cropped or resized?
4) Open your image using Gimp.
5) Use the Crop tool to trim down the edges.
6) Play around with the image size: (Option A or B)
1) Use the Scale tool. (This only works on the selected layer, currently we only have one.)
2) Go to Image > Scale Image… > Enter a new width or height.
How do your changes affect the resolution when you look at the saved image?
Exercise 1 – Create images using PowerPoint
Overwhelmed by all the options in Gimp? Check out the Gimp reference pdfs in the class directory.

2. Exercise 4 – Playing with photo effects
Open one of the portrait images. Do the following (try them in combination or each one separately.)
1) Filters > Décor > 2) Filters > Distorts > 3) Filters > Artistic > 4) Colors >
Remember:
Ctrl + z to undo
Exercise 3 – Selective color
1) Open the nature-01.jpg image.
2) Duplicate the background layer. Right-click on it in the Layers dialog and select “Duplicate Layer”
3) Make the black and white version. Go to Layer > Colors > Desaturate…
I prefer the “Luminosity” setting, but you can select each to see the difference. Click “Ok”
4) In the Layers dialog, right-click on the black & white layer and select “Add Layer Mask…” > Keep the
default “White (full opacity)” and click “Add”.
5) Make sure the white mask is selected. Then click on the Brush tool, and start painting on the butterfly.
Instead of adding pure black to the image, you should see the blue of the bottom layer show through.
It’s like you’re painting a hole in the top layer.
6) If you go outside the lines, switch the color to white and you’ll fill-in the mask.
Also try changing the brush from a hard circle to a fuzzy circle and observe the difference it makes.
7) When you’re all done, save the file with a new name as a .jpg
Exercise 5 – Original composition
Feeling creative? Use the example images and everything you’ve learned to create a multi-layered composition.
Hint: You can copy and paste layers from one image in Gimp to another.