Batch Rotate a Group of Images with Preview for Mac OS X

If you have a group of pictures that are orientated incorrectly that you need rotated, you can do that in Mac OS X without any third party apps with the help of the bundled Preview app.
- From the OS X Finder, select the collection of images you wish to rotate and hit Command+O to open them all into Preview
- In Preview, click an image thumbnail in the sidebar and then hit Command+A to “Select All”
- Now hit Command+R to rotate the picture 90 degrees clockwise once, hit Command+R again to continue rotating until you find the desired orientation of the pictures. Notice while this is happening that all thumbnail images are rotating.
- Hit Command+S to save the changes to image orientation

This assumes your default image editor is set to Preview. If not, launch Preview separately and then drag the group of images into Preview to perform the same task.
Preview is a fairly powerful app that is often underutilized for batch photo processing tasks, I use it frequently to batch resize images for wallpaper posts and other purposes, it’s quick, lightweight, and much less demanding on resources than Photoshop for such tasks.

This is stupid. Why are there five steps to rotate a simple picture?? Why cant I just click on the thumbnail and rotate the image? Mac can be so damn frustrating at times!!
This worked for me, but according to the information in my finder, all of the images were reduced in size by roughly 2/3. They went from approximately 3mb to 900kb. Why is this happening?