Depending on which view you are using the editor, standard or full view the picture button should be in the places circled in purple in the pictures below

Full screen view

Do you see the button here and these displays or do you see something different? Are you seeing the following display with the source button hightlighted in blue like this

If this is what you see then you are working in the source code mode. If you press source again it will go back to the display mode for you to edit and add images to and then you press the source code button again to copy the edited/finished code.