How to Enlarge an Image Using GIMP

Image editing programs like GIMP are ideal when resizing images. Enlargements can be done in GIMP, however it is recommended to keep enlargements minimal since quality can be easily lost. For example, enlargements would be made for situations such as one needing a document to print with a larger document size or need the image to have a higher resolution (while retaining document size).

1. With GIMP open, go to File > Open and select an image

You may right-click and save the tiger image below to use it as a practice image.

Note: When enlarging images, it is recommended to clean up dust and scratches or any noise before enlarging because these items may be magnified in your enlarged image.

(Follow along by right-clicking on the tiger image above and saving it!)

2. Go to Image > Scale Image

3. A Scale Image dialog box will appear like the one pictured below

4. To see the Image Size in inches or a value other than pixels, use the drop down beside the values

5. Enter new Image Size or Resolution values

The original image was 10″ x 6.667″. Lets say we wanted to enlarge this image to a 12″ x 8″ so that it can easily be printed and framed. We want to keep the 300 resolution, so all we need to do is type in image size dimensions. In this example, we increased the document width from 10″ to 12″ and the height from 6.667″ to 8″. 

6. Select Interpolation method

What does this mean? Basically, GIMP will have to create new pixel information in order to enlarge the image. 

Cubic – The color of each pixel is computed as the average color of the eight closest pixels in the original image. This usually gives the best result, but it naturally takes more time. Sometimes this method is called “Bicubic”.

Sinc (Lanczos3) – The Lanczos3 method uses the Sinc mathematical function and performs a high quality interpolation.

(Interpolation definitions from http://docs.gimp.org/)

7. Click Scale to accept the changes

Congratulations! You have successfully enlarged an image! 

In this example, we enlarged our image by increasing the image size from 10″ x 6.667″ to 12″ x 8″.