Image block

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Fields

Field	Type	Description	Required?
type	String	The type of block. For an image block, type is always image.	Required
alt_text	String	A plain-text summary of the image. This should not contain any markup. Maximum length for this field is 2000 characters.	Required
image_url	String	The URL for a publicly hosted image. You must provide either an image_url or slack_file. Maximum length for this field is 3000 characters.	Optional
slack_file	Object	A Slack image file object that defines the source of the image.	Optional
title	Object	An optional title for the image in the form of a text object that can only be of type: plain_text. Maximum length for the text in this field is 2000 characters.	Optional
block_id	String	A unique identifier for a block. If not specified, one will be generated. Maximum length for this field is 255 characters. block_id should be unique for each message and each iteration of a message. If a message is updated, use a new block_id.	Optional

Usage info

An image block, designed to make those cat photos really pop. Supported file types include png, jpg, jpeg, and gif.

Examples

The following three examples show different ways to get the following result:

An image block using image_url:

{
  "type": "image",
  "title": {
    "type": "plain_text",
    "text": "Please enjoy this photo of a kitten"
  },
  "block_id": "image4",
  "image_url": "http://placekitten.com/500/500",
  "alt_text": "An incredibly cute kitten."
}

An image block using slack_file with a url:

{
  "type": "image",
  "title": {
    "type": "plain_text",
    "text": "Please enjoy this photo of a kitten"
  },
  "block_id": "image4",
  "slack_file": {
    "url": "https://files.slack.com/files-pri/T0123456-F0123456/xyz.png"
  },
  "alt_text": "An incredibly cute kitten."
}

An image block using slack_file with a id:

{
  "type": "image",
  "title": {
    "type": "plain_text",
    "text": "Please enjoy this photo of a kitten"
  },
  "block_id": "image4",
  "slack_file": {
    "id": "F0123456",
  },
  "alt_text": "An incredibly cute kitten."
}