Mac storage basics · Mail, Messages and chat apps
Where are Messages attachments stored on my Mac?
Short answer: In your Library under Messages → Attachments. Don't delete there directly; remove attachments inside Messages or from the Messages section of Storage settings.
In your Library under Messages → Attachments. It can grow to many gigabytes of photos and videos from conversations.
Don't delete files there directly — Messages can show broken attachments or behave oddly. Delete attachments from within Messages (in a conversation's details) or from the Messages section of Storage settings, or shorten how long messages are kept. See reducing Messages storage.