If you want to use the alignleft/alignright options for your images then you’ll need to reduce the value for the content area.
There’s about a -168px pull on either one of the alignments so you’ll need to take that in to consideration when setting the content width.
Alternatively you can use a custom CSS plugin and add the following code to adjust the pull – amend according to which alignment is used….
.full-width .site-content blockquote.alignleft,
.full-width .site-content img.size-full.alignleft,
.full-width .site-content img.size-large.alignleft,
.full-width .site-content img.size-medium.alignleft,
.full-width .site-content .wp-caption.alignleft {
margin-left: -168px; /* Change this value */
}
Remember to remove the elements you do not want to adjust.
Regards,
Zulf