When you open up to post, first you can write under the Compose tab.
Next to it, you will see a tab that says Options above. After writing, then
click that and a window opens and you can browse inside your folders for an image to upload.
It has to be at or less than 90 kb in size, otherwise, you'll need an offsite image host,
such as Imagevenue.com, Nudiehost, etc. that allow larger sizes and adult content.
You can change the image by Editing your post and removing the pic if it doesn't look right.
(Oh, I thought he meant put an attached pic in a post)