Difference between Cropping, Scaling, Resizing & Changing Aspect Ratio of an Image?

Question

I am too confused in understanding different terms used with sizing of an image. What is the difference between:

1. Cropping an image
2. Resizing an image
3. Scaling an image
4. Changing Aspect-ratio of an image

Especially Resizing vs Scaling!!!

Answer 1

1. Cropping an image

Cropping is the removal of unwanted outer areas from a photographic or illustrated image. The process usually consists of the removal of some of the peripheral areas of an image to remove extraneous trash from the picture, to improve its framing, to change the aspect ratio, or to accentuate or isolate the subject matter from its background. Depending on the application, this can be performed on a physical photograph, artwork, or film footage, or it can be achieved digitally by using image editing tool.for more info refer https://en.wikipedia.org/wiki/Cropping_(image)

2. Resizing and Scaling an image

When working with raster images (pixel-based) it is important to understand that scaling an image in programs, such as Word, Powerpoint, InDesign, or Dreamweaver, does not actually resize the image, but rather stretches images larger or scales them smaller. When scaling, the resolution is not adjusted to best suit the new size, rather the pixels are stretched and can appear pixelated.

The most common side effect of scaling an image larger than its original dimensions is that the image may appear to be very fuzzy or pixelated. Scaling images smaller than the original dimensions does not affect quality as much, but can have other side effects. For example, if you upload a very large image to a website and scale it down to a smaller size, the website still must load the full size version of that image and could cause the web page to load more slowly.

For more details please refer https://guides.lib.umich.edu/c.php?g=282942&p=1885347 and http://glab.media/image-cropping-and-resizing/

3. Changing Aspect-ratio of an image

An aspect ratio is a proportional relationship between an image's width and height. Essentially, it describes an image's shape.Aspect ratios are written as a formula of width to height, like this: 3:2. For more info please refer squarespace.com