The picture mode on a TV has to do with the dimensions of the image that your TV displays. Like most other TVs, the LG Smart TV allows you to change the default dimensions. This tutorial will show you how.
Change Picture Mode on LG Smart TV
Press the Home key on your remote, and select the cog icon (in the top-right corner) to access the Settings menu.
Go to the Picture section > Picture mode.
Once there, you can choose between Vivid, Standard (Default), Eco, Cinema, Soccer, and Game mode.