Fit thumbnail on Facebook galleries
By adding -70% and -10% to the options at the end of the shortcode I can control how the thumbnail fits into my custom feed. The result looks like the below. If I do not add a percent the photos will be centered as depicted in the second photo. Below is example of the full shortcode too.
[ fts facebook id=bugatti posts=20 title=no description=no words=24 type=albums image_width=250px image_height=250px space_between_photos=1px hide_date_likes_comments=no center_container=no image_stack_animation=no image_position_lr=-74% image_position_top=-10% ]
Without the -74% and -10% option.