An illustration is a visualization created by an artist. It is a drawing (or painting, collage, engraving, or iconographic.) that helps convey a visual message. Among other functions, there are:

• Evoking positive emotions
• Tapping into nostalgic feelings
• Livening up content that is dry or dense
• Reinforcing or shaping your brand’s identity in your product
• Explaining what the product is about
• Generally making the UX more enjoyable