CropResize - Cropping & resizing function (Avisynth & VapourSynth versions)
The purpose of the script
The main goal of CropResize is to crop and resize without having to worry about calculating aspect error or distorting the picture. Rather than distort the picture as traditional resizing does when the input and output aspect ratios don't match, the script crops or adds borders instead. It can apply sub-pixel cropping when required.
Despite the numerous options, basic usage is fairly straightforward.
Source: Doom9 forum thread
Croppie
Croppie is a fast, easy to use image cropping plugin with tons of configuration options
https://foliotek.github.io/Croppie/rcrop
Responsive Cropper (rcrop) is a JQuery plugin that lets you select an area from an image and prepare crop information to send it to the server.
https://github.com/aewebsolutions/rcrop