Go to ImageShack. After taking a screenshot with the print screen button(see after this sentence), insert it in paint(paste or ctrl+v).




Then, save it as a name that is easy to remember.


On ImageShack, click browse (it's a button that says browse. Look for the image you just saved in "My Pictures", or wherever you have uploaded it, then click on it. Then, select the items you want(usually resized set to OFF). Now click Upload. Go to the very bottom and it will say "Direct link to image". Copy the link that you are given.


Now, start editing a post or start a new post and click the image button, while having the link selected.

There, you now have your image. Below is the format:
You can leave the width="#" or height out, because that's only for resizing it.