ImageKit's real-time image manipulation allows you to resize and crop images. While cropping, you may want to preserve a certain part of the image. Media library allows you to define a focus area on the uploaded image files and later crop around it using fo-custom URL parameter.
How to define a custom focus area on image files
Right-click any image file in the media library and select the "Custom Focus Area" option. Now you can resize and drag the rectangle on the image to define the focus area.