Before proceeding, make sure you are in Basic View by choosing

Select a problem with an image and open the Visual Editor. (For more information about opening and using the Visual Editor, see the article Editing a Problem Using the Visual Editor)
Select the image by clicking on it.
Use the alignment buttons on the toolbar to change the horizontal alignment of your image.
Right-click on the image and choose Image Properties.
Use the Image Properties dialog to adjust the scale and vertical alignment of the image.
Click OK to return to the Document Tree.

For information on inserting images, see the article Inserting Images Using the Visual Editor .