If you want to make a clean install of the new OS X Mavericks or even the older versions of Mac OS X, than I strongly suggest you to create a bootable OS X key or a drive.
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.
Camera images usually contain additional description about camera settings and scene information of the the picture taken. By using EXIF, you can view this data online.
If you are a fan of lomo style cross-processed photos then this should be right up your alley. We will create a time saving Photoshop action, you can later on use on your photos.