Couple different ways........If you have a photobucket account (which is free, and prolly the easiest, by the way www.photobucket.com) you can upload them from your computer to photobucket. From there you can make them a little smaller, and copy/paste the image tag below the image. Paste the tag in your post and change the to " />.

Or you can upload them straight to your computer. You will need photoshop or some other program to resize them because if doing this method the photo needs to be under 100kb. At the bottom of the message window it reads "Click here to upload!" and next to it is "Embed picture in post" check that box and click the link. Click the browse button and find your photo....then upload. Sounds alot more difficult than it is....It's really very simple.