How To Resize Images in GIMP
The GNU Image Manipulation Program or “GIMP” is amazing free, open-source software created and maintained by a dedicated group of volunteer developers. It’s an incredibly full-featured image editor with powerful tools to make the most of your graphics and photos. Don’t be intimidated by its complexity; sometimes it’s just a really useful tool for simpler tasks.
There are numerous reasons why you might want to resize an image. You may need a very specific size to print, you may need to downsize to reduce file size, or you may be using multiple images in a design and need to resize different parts of your composition. In this article, we’re going to look at numerous tools that GIMP uses to resize images.
How to resize an image using Scale Image in GIMP
The easiest way to resize an image in GIMP is to use the Scale Image feature. With Scale Image we can precisely set the image size in a range of units (percent, pixels, mm, inches, etc.) and set the image resolution, which is essential for images to be displayed on screen or printed.
GIMP’s image scaling feature resizes everything on the image canvas, regardless of layers. So if you have a background image layer and multiple logos on layers above the background, all of those layers will be scaled appropriately. It’s therefore useful when you’ve been working on a larger design image and then need to scale it to a specific size for a web application or other size-sensitive use.
1. Click Image >> Scale Image.
2. Resize the image by setting the width and height. The “chain symbol” can link the two dimensions together so that changing one changes the other, based on the image’s aspect ratio. These can be separated, but the picture can be distorted. Image units can be changed using the px dropdown menu.
3. Use the X and Y resolution and click Scale to set the image resolution. Typically, print resolutions are higher than screen resolutions and are measured in pixels per inch (ppi).
The tool palette, located at the top left of the screen, houses many useful tools, some of them hidden. The Scale Tool selects the currently active layer, or any area you’ve selected, and scales it in a manner similar to Scale Image.
The scale tool is especially useful when scaling an image on a separate layer. You can import an image into GIMP by clicking on a separate layer File >> Open as Layers and select the image you want to add. Each layer can be selected from the layers menu (bottom right) and scaled independently of the overall image.
1. Click on the scale tool, hidden in the upper left palette. Hover your mouse over the icons to see all the tools they contain.
2. Set the desired size and click Scale. Note that the user interface is very similar to the Scale Image. We can scale using the image’s aspect ratio without stretching or distorting it. The units of measurement can also be changed using the drop-down menu.
3. Left-click and drag the handles around the image to interactively scale the image. You’ll notice that if you select the lock icon in the Scale tool dialog box, you’ll keep the image’s aspect ratio and update the image’s new dimensions in the appropriate input fields.
4. Click Scale in the dialog box to apply the scaling and close the tool.
How to crop content in GIMP
If you’ve used the scaling tool to reduce your image size, you’ll notice that the canvas has retained the original size of the image. This appears as checkered sections of blank canvas visible around your image.
To resize the canvas to the new image size, click Image and choose Crop to Content. This will automatically shrink the canvas to fit your resized image.
Fit canvas to layers
If you’ve used the scale tool to enlarge your image, you’ll notice that the image is partially obscured because it doesn’t fit the original canvas. To fix this usage File >> Image >> Fit Canvas to Layers. Clicking this option will automatically enlarge the canvas to fit your larger image.
Changing the print size in GIMP
1. Click Image >> Print Size to open the dialog.
2. Set the desired print size of the image and click OK to set. Remember that the units of measure can be changed using the drop down menu. Changing the print size does not change the number of pixels that make up an image. So if you downsize an image for printing, you will find that the resolution, the number of pixels per inch or mm, increases. As you increase the size of the image, the resolution will decrease accordingly. As you increase the size of an image, the number of pixels in a given area decreases as they spread out. This means that if you drastically increase the size of an image, the quality of the image will decrease.
With the above techniques, you have a wide range of tools to control both the size and resolution of the images and designs you create. These are just the tip of the GIMP features iceberg, but they’re a good set of tools to learn to use to boost your confidence while exploring this excellent application.