Gimp Tutorials

GIMP (Gnu Image Manipulation Program) is a popular and free open source cross-platform image editor available in versions for Linux, Windows, and Mac.  It is seen as a viable alternative to Photoshop.

GIMP provides the tools needed for high quality image manipulation from retouching to restoring to creative composites.  It also offers graphic design elements.

This course offers short tutorials that will help you learn how to use GIMP to manipulate and improve images.

About This Course

This is the first content box for the ABOUT section

GIMP Basics

This is the first content box for the BASICS section.

Cropping an Image

Bob meant well with his presentation...

Bob meant well with his presentation...

Only... His new manager is thinner!

Learning to Crop

We shouldn't be too hard on Rookie Bob!  If he doesn't find good help soon, he will learn to do what most of us do to avoid any distortion that extreme:   Just use the presentation software to stretch it the other way until it looks about right, chop it off here and there, and hope we don't have to ever insert images anywhere but on a slide!

A better, proactive approach is to gain control of the situation from the start!  Learning to crop with the power of an image editor (such as GIMP) helps you improve the composition of your images as well as ensure a proper and proportional fit.

Let's get started!

Exploring GIMP's Crop Feature

The Gimp screenshot below was captured after a portion of an owl picture was selected for cropping but before the action of cropping had actually taken place.   Explore by clicking the blinking hotspots to find out more about cropping with GIMP.

Knowledge Check #1: Identify the GIMP Crop Tool

The image below represents all the tools in the GIMP Toolbox.  Please locate and click on the CROP TOOL.

Knowledge Check #2: What final step COMPLETES the crop action?

Pressing the ENTER key on your keyboard also works!

  • Click on the image OUTSIDE of the SELECTION RECTANGLE.
  • Click on the image INSIDE of the SELECTION RECTANGLE.
  • Drag mouse across image from LEFT to RIGHT.

Manipulating the SELECTION RECTANGLE

Now that you have a general idea about cropping in GIMP, let's move on to see how you can gain lots of control in how you do it!

Remember how the owl had been selected with a SELECTION RECTANGLE in the screenshot displayed earlier?  Well...

The OPTIONS chosen in this dialog box

Tool Options Dialog Box

affect the shape and size of your SELECTION RECTANGLE
and how it moves (or doesn't move) as you drag it across your image.

Taking a few minutes now to understand these options and to learn to set them to your advantage can save you a lot of time and headaches later.  They will give you precise control over your cropping!

 

Think of the crop tool's Selection Rectangle as a picture frame
that floats over your image, letting you see all your framing possibilities.

Picture frame over lighthouse pic

 

Wanna see it float?   :)

 

Now explore the highlighted option settings below:

Knowledge Check #3: Match the Cropping Terms

  • Aspect Ratio
    Proportional relationship between width and height
  • Fixed
    Locked
  • Allow growing
    Ignore image boundaries
  • Crop Tool Guide
    Center Lines

Knowledge Check #4: Lock the Crop Tool

Locking the Crop Tool is a three-step process. 

(The same dialog box image is shown for each of the three different questions below.  Answer each question by clicking in the box that is directly below the question.)

Let's Crop!

So, now that you know all about the tool, let's go through the steps of using it!

Assuming you have the GIMP program open and an image loaded into the image window, do the following:

  1.  Click on the CROP TOOL in the toolbox.
  2.  Enter the desired options in the TOOL OPTIONS dialog box.
  3.  Click and drag across the image until you have selected the desired area.  Release mouse.
    1. To MOVE the SELECTION RECTANGLE to a different part of the image (think "floating picture frame"), hover over it until you see a 4-headed arrow, then click and drag the rectangle anywhere you want.
    2. To RESIZE the SELECTION RECTANGLE, hover over it until you see a triangle representing an arrow in the direction you want to expand or contract.  (If aspect ratio is fixed, it doesn’t matter which of these triangles you click on because it will resize in all directions in order to preserve set ratio.)  Drag the arrow inward to make selection smaller (encompassing less of the image) or outward to make selection larger (encompassing more of the image).  You can also type the desired dimensions into the SIZE area of the TOOL OPTIONS box.  (Again, if aspect ratio is fixed, changing the value of one of the dimensions will automatically adjust the other to protect ratio.)
    3. To start selection process over, just click somewhere outside the image or press the Escape key on your keyboard.
  4. Click once again on the selected area to complete the cropping action.
  5. Unhappy with the result?  Click UNDO in the Edit menu (or press Control+Z on your keyboard) and try it again!

Just a few more things:

GIMP will not let you SAVE an image with the extensions jpg or png.  Instead, choose EXPORT AS on the File menu, choose the desired extension in the dialog box, and export it to your desired destination.

Also, make sure you have a backup copy of the original image... just in case you need it later!

To get a copy of these cropping instructions, click the link below:

https://docs.google.com/document/d/1Iro8NqtFZ6fkYuvqowrloluI7iWo7z_UkTcTLa9X1Jk/edit?usp=sharing

That's it!

Congratulations!

You may now say...

Hello - I am in Control badge

Removing Background from an Image

TLW use proper tools to remove a background from an image.