Run the program and drag and drop the files you want to modify. Then, decide what you want to modify and apply changes.
Change the size of all of them to a unique one, reduce them according to a percentage, rotate, change the format (JPG, BMP or PNG), change the name to all according to a pattern,...
As you can see, you can perform many modificatinons, all of them in a second and without having to rack your brains.
Choose the ones you want to apply and press OK. Wait for a fe seconds and enjoy your new photos. Easy and with great results, that's exacly what you need.