Image
A standalone image with an optional title row.
image renders a single image, either from a public URL or a title-less caption. Use it to show a
screenshot, photo, or diagram inline in a message, modal, or App Home surface.
Fields
typestring
Always `image`.
stringimage_url?string
A public URL to a GIF, JPEG, PNG, or BMP. Mutually exclusive with `slack_file`.
stringslack_file?{ id?: string; url?: string }
A file already uploaded to Slack, referenced by `id` or internal `url`. Mutually exclusive with `image_url`.
{ id?: string; url?: string }alt_textstring
A plain-text summary for screen readers. Doesn't render on screen.
stringtitle?PlainTextElement
A caption shown above the image. Plain text only; `mrkdwn` isn't supported.
PlainTextElementblock_id?string
A unique identifier, up to 255 characters.
stringExamples
Without a title
With no title, Slack still reserves the title row’s height for the expand caret, so the image sits
at the same vertical offset either way.
With a title
Referencing a Slack file
Since a slack_file needs a live workspace to resolve, this renders as the alt-text fallback rather
than the actual photo.