After an image is uploaded to WordPress, we can set it to have new image dimensions (width x height) in addition to the three default sizes automatically generated by WordPress. The new image size ...
Besides the three image dimensions generated automatically for images uploaded in WordPress, we can specify the theme to generate more sizes. These new sizes are great for theme development and styling purposes.
Here are the ways to do it: Manually and by using a simple plugin.
When an image file is uploaded to WordPress, various copies of the image is created and stored. Normally, three additional copies of an image will be stored with the original one. These copies are ...
Different copies of a single image are made when it is uploaded to WordPress. This allows us to use the different dimensions depending upon how big or small we want to display them. Using large images to display them as small ones is possible, but it wastes bandwidth on both ends and increases the page loading times. So for adding images in posts, it is recommended to have the exact resized dimension that is being shared.
That is why three images are generated of thumbnail, medium and large size. The original image is kept as well. So, effectively you have four total images instead of a single one. That is if the dimensions are large enough to generate all the sizes.
There are different ways to configure these image dimensions for your convenience.