<picture> tag

example 1 — basic

• default: 320 x 320
• between 480 and 640 px viewport width: 640 x 640
• above 640 px viewport width: 960 x 960

example 2 — art direction

• default: 320 x 320
• above 480 px viewport width and landscape format: 852 x 640
• above 480 px viewport width and portrait format: 640 x 852