Its pretty easy
1-start a new post
2- click the "CLICK HERE to Upload your photo(s) link (in red and blue text, just above the new post editing field.
3-New window pops up, navigate to your file on you hard drive and click upload.
4-Wait a few seconds and it will show your picture after the upload.
5-It will provide you a link to the picture. Copy and Paste the WHOLE link into your post and you're finished.
You can also preview your post to make sure the photo shows before posting.
Hope that helps