Happy as a lark
• All smiles
• Beaming
• Cheerful
• Cheerful, in art
• Cheery
• Gay
• Gleeful
• Having a laugh
• Jocular
• Jolly
• Laughing
• Laughing in the Louvre
• Laughing it up
• Merry
• Mirthful
• Not at all blue
• Pleasingly mirthful
• Smiling