If you accidentally forgot credit, posted the wrong image, or something as such, instead of posting another post why not edit the post for less inconvenience?
In the top, right corner of each of your posts there should be 7 buttons- Multi-Quote, Quote, Edit, x, ip, !, and ! with a "stop sign" across it. Click the "Edit" button. It should take you to the page to edit your post. You can then edit it as needed.
If you have questions about this post here!