Adding an image to a post is pretty simple since Org-mode offers a special link scheme for that. Image source file can be stored anywhere since its path is valid. During the export process, the image file is copied into a folder related to the post and all links are corrected to point to its new location.
For example, the following piece of code will copy the emacs-logo.png from the current
directory and is is then copied into it into
tips/2012/08/21_adding-an-image-into-a-post/emacs-logo.png.
file:emacs-logo.png
The HTML result is something similar to:
<img src="21_adding-an-image-into-a-post/emacs-logo.png" alt="21_adding-an-image-into-a-post/emacs-logo.png" />
A best practice is to have all files info a /files folder. Then you can
create a sub-folder for each posts such as:
/files/post1/file1/files/post1/file2/files/post2/file- …