Resizing an Image in GIMP
One of the most useful things you can learn to do on your Raspberry Pi is to resize an image. All computer images are made up of pixels, which are tiny colored dots. My camera produces images that are 4272 pixels wide and 2848 pixels high. High-quality images like that are great for printing photos, but if you just want to use pictures onscreen, quality comes at a price. That level of detail requires a large file size, and big files can significantly slow down your Raspberry Pi. Often, you can use a lower quality image without noticeably affecting the end result, assuming your finished result will only be displayed on screen.
Here’s how you can resize an image using GIMP:
1. Click to open the Image menu at the top of the screen and click Scale Image.
A window like Figure 7-2 opens.
2. In the Width box, enter the width you would like your final image to be in pixels. Press Enter when you’ve finished entering your width.
If you wanted to put a holiday snap on your website (see Chapter 8), you probably wouldn’t want it to be more than 500 pixels wide. Anything larger than that can be hard to fit into a web page design and might take a long time for visitors to download. If your screen only displayed 1024 pixels across, you probably wouldn’t want to use an image much larger than 800 pixels wide.
When you enter a new value for the Width, the Height is updated automatically, so the image stays in proportion and doesn’t become stretched. You can also enter ...