You don't need Photoshop or some other advanced piece of software to resize a large number of images at once. You can use Microsoft Office Picture Manager which is part of the Office suite.
Pixlr is a free and probably the best web based image editor. I will show you how to open and and resize an image, I'm sure you will be impressed how well the web app actually works.
Adobe Photoshop CS6 comes with many great features, let me show you how to turn a daylight photo into a photo that looks like it's been taken at evening, sundown or at night with only a click.
