What is Image Scaling?
Image Scaling refers to the enlarging or reducing the size of an image by increasing or decreasing the number of pixels it contains. Basically it is a resizing of the entire image, ideally without losing any of the details.
Image Scaling is a menu driven program and can be done by going to image and clicking on the Scale Image option. A Scale image dialogue box is displayed which will have the details like height, width and resolution details on it. All you have to do is choose the size and resolution you want your image to be after scaling.
When is Image Scaling Required?
Enlarging an image may be necessary in cases where you may want an enlarged copy of a document or a picture to fit the printed page. You may on the other hand, be required to shrink the image in order to fit into a webpage. Both these involve the reworking of the pixels on the image. Pixels may be referred to the information about the image on the body of the image. Since the image may be loaded in RAM after it is loaded, the reduced image uses less pixels and hence less memory size.
Functions and Effects of Image Scaling
The places where you might find the image besides the RAM is on the image file, on your display screen or on paper after it is printed. The quality of an image depends on its resolution which is called pixel density per unit square inch. Scaling the image therefore, affects picture quality too. The image may be affected in following ways.
- In case the image contains some layers then the shrinking of an image may reduce the layers on the image to nothing. In that case a warning is shown to you before making the image shrunk.
- The process of enlarging a layer in an image involves the calculation of new pixels from the existing one by the GIMP by ‘Interpolation’. We should remember that no new information can be added to the image by interpolation.
- In case there are a few places on the image that has no details, then even after interpolation no new information will be added on it.
- In fact enlarging the layer would make the image blurred in this case.
- In the same way, if you reduce the layer then the image may lose some of its quality by the removing of pixels.
- The image quality may be improved by using the sharpen filter.
- Adding or reducing pixels on an image is called ‘Resampling.’