2. Adjust Display Settings
You'll be moved to the display settings screen.
Display As field = select the desired display (Original is shown in the example).
Alignment field = select the desired alignment (Center is shown in the example).
Alt Text field = if you don't have any alternative text here, you should.
Title Text field = enter some optional text to be used as a tooltip, if desired.
Link Image field = if you would like to link this image to something, enter the full URL here.
Click the Submit button.
Note that your image will not appear centered in the text editor. It will appear centered in the saved node, however.