Python script for automated cropping of images

I have a python script which automatically takes screenshots of a certain webpage on a defined interval (e.g 15 mins) and save it to a folder and I need a modification in this script and the modification will be like it will open two chrome windows now and I can define two different intervals simultaneously for taking screenshots and a freshly created script which will crop this screenshots in a defined aspect ratio and laid it to end to end save in PNG format with the file name same as source screenshot folder with current date .