WordPress is great for resizing the resolution and file size of images you upload using its editor. If you upload a huge 3000 x 2000 pixel 8MB digital camera snapshot, WordPress will do the work to reduce the image to a web-friendly 600 x 400 pixel 100KB file.
And now (as of WP version 2.9) it’s also possible to crop and rotate your images from within WordPress. No Photoshop required! Watch this video to learn how.