Introduction to Image Editing - GIMP - The Image Manipulation Program

If you are interested in creating your own images for use in RightBooth, then you really need to learn how to use image editing software.

There are many applications on the market, they all offer different tools and they all come with different price tags, but in this article we will be focusing on a package called GIMP.  Why GIMP?  Well, first it is completely free! and second, it offers a fantastic range of image editing features that rival many of the pricey packages on the market.  You really can't go wrong with GIMP and we use it all the time here at Aire Valley Software.

So go ahead and install it from the GIMP download site:   https://www.gimp.org/downloads/

Note that this article is based on using GIMP 2.8.22.  We will cover the basics of what you need to know about image editing

1 Loading, Converting and Saving Images
When you run GIMP, it will show an empty window with a menu above.

To load an image into GIMP

• On the GIMP menu click  File then Open to load an image.
• The image size is shown along the top:  480x360 pixels
• The filename is shown at the bottom: overlay0.jpg
• The view size selector is located at the bottom.  Currently this is set to 100% but you can change this to any value to allow you to zoom into the image, then you can use the scroll bars to look at any area in detail

To save the image...

• On the GIMP menu, click File then Export As
• On the Export Image window, in the Name text box, you can name the file, in our example: roseheart.
• Notice we have added ‘.png’ to the end of the filename. This will cause GIMP to save the image in PNG format.  If you want to save it as a JPG, BMP or a GIF, simply added .jpg, .bmp or .gif to the filename.
• Use the Places and Name boxes to browse to the folder where you want to save the image.  In our example we are saving the file to the RightBooth Media Library Overlays folder.
  
• Click the Export button to save the image.

​Remember: In this process we have actually saved a copy of the original image and we have also converted it from JPG to PNG format during the save process.

2 Image Resizing

​​Images can be VERY big, especially photographic images captured with modern digital cameras so these days it is not unusual to see image sizes approaching 12000 x 12000 pixels.

It is important to remember that RightBooth (or any other package for that matter) will not perform well if you start adding overly large images onto event screens so we recommend you resize large images and re-save them at a smaller size,
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Here you can see the rose and rings image is 4000x3000 pixels.
Too big !
We want to use this as an event screen background.  Our computer screen display is set to 1920 x 1080 pixels, so there is really no need for this image to be any bigger than 1920 pixels wide.

We will use GIMP to resize it.

• On the GIMP menu, click Image  then Scale Image
• In the Scale Image window, type 1920 into the Width text box.
• Then click the mouse into the Height text box and you will notice that GIMP automatically sets the Height to 1440.  This is because the Aspect ratio lock is set (see screen shot).  If you click the lock icon it will unlock, allowing you to change the Height independently from the Width.
• Click the Scale button to resize the image.
• Back at the GIMP menu, click File then Export to rose and rings.jpg

This will save the newly re-sized image over the original file.

​If you'd rather not overwrite the original file then use Export As

3 Image Cropping

​Here's another image we'd like to use as an event  background.  We've loaded it and resized it to 1920 pixels wide, but the height is 1919 pixels. 

This is far taller than our desktop display height which is only 1080 pixels so if we load this image into RightBooth it will be squashed up and distorted vertically to fill the screen. 

​This image lends itself to being cropped by removing the areas above and below the hanging frames. 

We will use a GIMP Select tool for this purpose.

• Make sure the GIMP toolbox is showing by pressing Ctrl+B keys
• Click the Rectangle Select Tool on the toolbox
• Drag a rectangle across the image making sure its height is 1080 pixels.  Use the Zoom to help with this.  In our screen shot you can see we have started the rectangle outside the left edge of the image and dragged past the right hand edge of the image.
• You can also move the whole rectangle around by dragging the centre
• On the GIMP menu, click Image then Crop to Selection to crop the image to 1920 x 1080 pixels
• ​Re-save the image

This image is now the perfect size and shape to be used as an event background.

This article has introduced you to the basics of image editing: loading, converting, resizing, cropping and saving images.
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We will explain more GIMP editing features as part of other How To tutorials.