Alternatively, the most popular site amongf AB members is probably Upl.co.
http://upl.co/
Click the green button.
Navigate to the location of your image file.
Double-click on it.
Click in the 'Direct link' field, to highlight it.
Then right-click and select 'Copy'
Come to an AB post, right-click and select 'Paste'.
Job done!
(Note that it's best to put the link on a line by itself, so that it doesn't get mixed up with anything else that you type).