Image Description¶
The Image type is defined in ActivityStreams Vocabulary.
In this support table, we only consider how the image description, commonly called AltText is handled. Image descriptions are important from an accessibility standpoint, see WCAG 2.2. Text Alternatives.
It seems that certain implementations, e.g. firefish, store the image description on a per image URL basis and not for every instance of an image reference.
Examples¶
Example 1¶
activity
{
"@context": [
"https://www.w3.org/ns/activitystreams",
{
"Hashtag": "as:Hashtag",
"sensitive": "as:sensitive"
}
],
"type": "Create",
"actor": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://gotosocial/users/cookie"
],
"id": "http://pasture-one-actor/actor/s6xnA7b2594",
"published": "2025-07-15T09:41:23Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://gotosocial/users/cookie"
],
"id": "http://pasture-one-actor/actor/4pohS7hfq2g",
"published": "2025-07-15T09:41:23Z",
"content": "no description",
"attachment": {
"type": "Document",
"url": "http://pasture-one-actor/images/100.png"
},
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K06QBNDR9NEVWPH833AM6A74",
"created_at": "2025-07-15T09:41:23.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/actor/4pohS7hfq2g",
"url": "http://pasture-one-actor/actor/4pohS7hfq2g",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "no description",
"reblog": null,
"account": {
"id": "01K06Q91X1R92RNFKRJ5FN0A50",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-07-15T09:39:57.484Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon4.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon4.png",
"header": "http://gotosocial/assets/default_header.png",
"header_static": "http://gotosocial/assets/default_header.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 35,
"last_status_at": "2025-07-15T09:41:23.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K06QBP66CTG7HAWX0CQGSXNB",
"type": "image",
"url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/original/01K06QBP66CTG7HAWX0CQGSXNB.png",
"text_url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/original/01K06QBP66CTG7HAWX0CQGSXNB.png",
"preview_url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/small/01K06QBP66CTG7HAWX0CQGSXNB.jpg",
"remote_url": "http://pasture-one-actor/images/100.png",
"preview_remote_url": null,
"meta": {
"original": {
"width": 40,
"height": 40,
"size": "40x40",
"aspect": 1
},
"small": {
"width": 40,
"height": 40,
"size": "40x40",
"aspect": 1
},
"focus": {
"x": 0,
"y": 0
}
},
"description": null,
"blurhash": "L27co0xNfQxNxNjvfQjvfQfQfQfQ"
}
],
"mentions": [
{
"id": "01PNDDP5K9GH5G0V954907P8AZ",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}
Example 2¶
activity
{
"@context": [
"https://www.w3.org/ns/activitystreams",
{
"Hashtag": "as:Hashtag",
"sensitive": "as:sensitive"
}
],
"type": "Create",
"actor": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://gotosocial/users/cookie"
],
"id": "http://pasture-one-actor/actor/g-hp3-ZrdL8",
"published": "2025-07-15T09:41:24Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://gotosocial/users/cookie"
],
"id": "http://pasture-one-actor/actor/-Tfk8CyDwbQ",
"published": "2025-07-15T09:41:24Z",
"content": "text",
"attachment": {
"type": "Document",
"url": "http://pasture-one-actor/images/100.png",
"name": "name",
"summary": "summary",
"content": "content"
},
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K06QBPD0JS54Y6CBF2Z4XP5W",
"created_at": "2025-07-15T09:41:24.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/actor/-Tfk8CyDwbQ",
"url": "http://pasture-one-actor/actor/-Tfk8CyDwbQ",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "text",
"reblog": null,
"account": {
"id": "01K06Q91X1R92RNFKRJ5FN0A50",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-07-15T09:39:57.484Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon4.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon4.png",
"header": "http://gotosocial/assets/default_header.png",
"header_static": "http://gotosocial/assets/default_header.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 36,
"last_status_at": "2025-07-15T09:41:24.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K06QBPTRGTRBVDDPKZ2J2N4Y",
"type": "image",
"url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/original/01K06QBPTRGTRBVDDPKZ2J2N4Y.png",
"text_url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/original/01K06QBPTRGTRBVDDPKZ2J2N4Y.png",
"preview_url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/small/01K06QBPTRGTRBVDDPKZ2J2N4Y.jpg",
"remote_url": "http://pasture-one-actor/images/100.png",
"preview_remote_url": null,
"meta": {
"original": {
"width": 40,
"height": 40,
"size": "40x40",
"aspect": 1
},
"small": {
"width": 40,
"height": 40,
"size": "40x40",
"aspect": 1
},
"focus": {
"x": 0,
"y": 0
}
},
"description": "summary",
"blurhash": "L7QY#d}rfQ}r}roLfQoLfQfQfQfQ"
}
],
"mentions": [
{
"id": "01PNDDP5K9GH5G0V954907P8AZ",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}
Example 3¶
activity
{
"@context": [
"https://www.w3.org/ns/activitystreams",
{
"Hashtag": "as:Hashtag",
"sensitive": "as:sensitive"
}
],
"type": "Create",
"actor": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://gotosocial/users/cookie"
],
"id": "http://pasture-one-actor/actor/3JeKrTBx1CY",
"published": "2025-07-15T09:41:24Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://gotosocial/users/cookie"
],
"id": "http://pasture-one-actor/actor/07Y1uUmCbEQ",
"published": "2025-07-15T09:41:24Z",
"content": "text",
"attachment": [
{
"type": "Document",
"url": "http://pasture-one-actor/assets/FediverseLogo.png",
"name": "name",
"imageType": "image/jpeg"
}
],
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K06QBPD0XP852JRN6VEPXM6S",
"created_at": "2025-07-15T09:41:24.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/actor/07Y1uUmCbEQ",
"url": "http://pasture-one-actor/actor/07Y1uUmCbEQ",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "text",
"reblog": null,
"account": {
"id": "01K06Q91X1R92RNFKRJ5FN0A50",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-07-15T09:39:57.484Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon4.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon4.png",
"header": "http://gotosocial/assets/default_header.png",
"header_static": "http://gotosocial/assets/default_header.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 37,
"last_status_at": "2025-07-15T09:41:24.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K06QBQFY1JV4NM15MFVZ9ZZ0",
"type": "image",
"url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/original/01K06QBQFY1JV4NM15MFVZ9ZZ0.png",
"text_url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/original/01K06QBQFY1JV4NM15MFVZ9ZZ0.png",
"preview_url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/small/01K06QBQFY1JV4NM15MFVZ9ZZ0.jpg",
"remote_url": "http://pasture-one-actor/assets/FediverseLogo.png",
"preview_remote_url": null,
"meta": {
"original": {
"width": 1548,
"height": 1548,
"size": "1548x1548",
"aspect": 1
},
"small": {
"width": 512,
"height": 512,
"size": "512x512",
"aspect": 1
},
"focus": {
"x": 0,
"y": 0
}
},
"description": "name",
"blurhash": "LIB{x~.}9Fcn}gnOEUxBDlK[N1wi"
}
],
"mentions": [
{
"id": "01PNDDP5K9GH5G0V954907P8AZ",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}
Example 4¶
activity
{
"@context": [
"https://www.w3.org/ns/activitystreams",
{
"Hashtag": "as:Hashtag",
"sensitive": "as:sensitive"
}
],
"type": "Create",
"actor": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://gotosocial/users/cookie"
],
"id": "http://pasture-one-actor/actor/9gDlE7iTsJE",
"published": "2025-07-15T09:41:25Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://gotosocial/users/cookie"
],
"id": "http://pasture-one-actor/actor/mCvd_dL0DCY",
"published": "2025-07-15T09:41:25Z",
"content": "no comment in attachment",
"attachment": [
{
"type": "Document",
"url": "http://pasture-one-actor/assets/FediverseLogo.png"
}
],
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K06QBQC8QHDQPCGKSH8G7MK7",
"created_at": "2025-07-15T09:41:25.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/actor/mCvd_dL0DCY",
"url": "http://pasture-one-actor/actor/mCvd_dL0DCY",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "no comment in attachment",
"reblog": null,
"account": {
"id": "01K06Q91X1R92RNFKRJ5FN0A50",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-07-15T09:39:57.484Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon4.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon4.png",
"header": "http://gotosocial/assets/default_header.png",
"header_static": "http://gotosocial/assets/default_header.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 38,
"last_status_at": "2025-07-15T09:41:25.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K06QBR4JE1VQN5NQ52GWV456",
"type": "image",
"url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/original/01K06QBR4JE1VQN5NQ52GWV456.png",
"text_url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/original/01K06QBR4JE1VQN5NQ52GWV456.png",
"preview_url": "http://gotosocial/fileserver/01K06Q91X1R92RNFKRJ5FN0A50/attachment/small/01K06QBR4JE1VQN5NQ52GWV456.jpg",
"remote_url": "http://pasture-one-actor/assets/FediverseLogo.png",
"preview_remote_url": null,
"meta": {
"original": {
"width": 1548,
"height": 1548,
"size": "1548x1548",
"aspect": 1
},
"small": {
"width": 512,
"height": 512,
"size": "512x512",
"aspect": 1
},
"focus": {
"x": 0,
"y": 0
}
},
"description": null,
"blurhash": "LIB{x~.}9Fcn}gnOEUxBDlK[N1wi"
}
],
"mentions": [
{
"id": "01PNDDP5K9GH5G0V954907P8AZ",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}