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": [
"http://hollo/@john",
"as:Public"
],
"id": "http://pasture-one-actor/activity/O7x0J_Ir-SU",
"published": "2025-08-27T08:16:18Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"as:Public",
"http://hollo/@john"
],
"id": "http://pasture-one-actor/object/ZAFVsnNE7ZM",
"published": "2025-08-27T08:16:18Z",
"content": "no description",
"attachment": {
"type": "Document",
"url": "http://pasture-one-actor/images/100.png"
}
}
}
gotosocial
{
"id": "01K3GVAR18ADXGXGKYXJS3255G",
"created_at": "2025-08-25T14:50:17.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/object/LYaFtjMXRvA",
"url": "http://pasture-one-actor/object/LYaFtjMXRvA",
"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": "01K3GV8459F044M7E2J13WTR56",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-08-25T14:48:51.133Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon5.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon5.png",
"header": "http://gotosocial/assets/default_header.png",
"header_static": "http://gotosocial/assets/default_header.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 33,
"last_status_at": "2025-08-25T14:50:17.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K3GVARZFVVXRP68N7V82VZSV",
"type": "image",
"url": "http://gotosocial/fileserver/01K3GV8459F044M7E2J13WTR56/attachment/original/01K3GVARZFVVXRP68N7V82VZSV.png",
"text_url": "http://gotosocial/fileserver/01K3GV8459F044M7E2J13WTR56/attachment/original/01K3GVARZFVVXRP68N7V82VZSV.png",
"preview_url": "http://gotosocial/fileserver/01K3GV8459F044M7E2J13WTR56/attachment/small/01K3GVARZFVVXRP68N7V82VZSV.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": "L6O1OT}xfQ}x}xoMfQoMfQfQfQfQ"
}
],
"mentions": [
{
"id": "01KA518HV2YMVXQKRA76EF2ZJV",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}
hollo
{
"id": "0198ea99-6450-73eb-b8b5-bb856e26f710",
"created_at": "2025-08-27T08:16:18.000Z",
"in_reply_to_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/object/ZAFVsnNE7ZM",
"url": "http://pasture-one-actor/object/ZAFVsnNE7ZM",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "no description",
"reblog": null,
"quote_id": null,
"quote": null,
"application": null,
"account": {
"id": "0198ea98-1daf-74ca-ab5b-29bdfc9e43ad",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": false,
"bot": false,
"created_at": "2025-08-27T08:14:54.323Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://hollo/image/avatars/original/missing.png",
"avatar_static": "http://hollo/image/avatars/original/missing.png",
"header": "http://hollo/image/headers/original/missing.png",
"header_static": "http://hollo/image/headers/original/missing.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 0,
"moved": null,
"last_status_at": null,
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "0198ea99-658f-75f5-b56d-fc969dd34182",
"type": "image",
"url": "http://pasture-one-actor/images/100.png",
"preview_url": "http://pasture-one-actor/images/100.png",
"remote_url": null,
"text_url": null,
"meta": {
"original": {
"width": 512,
"height": 512,
"size": "512x512",
"aspect": 1
},
"small": {
"width": 512,
"height": 512,
"size": "512x512",
"aspect": 1
},
"focus": {
"x": 0,
"y": 0
}
},
"description": null,
"blurhash": null
}
],
"mentions": [],
"tags": [],
"card": null,
"emojis": [],
"emoji_reactions": [],
"poll": null,
"filtered": 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": [
"http://hollo/@john",
"as:Public"
],
"id": "http://pasture-one-actor/activity/a8BLymWw7_w",
"published": "2025-08-27T08:16:18Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"as:Public",
"http://hollo/@john"
],
"id": "http://pasture-one-actor/object/z7i5Hs9qisk",
"published": "2025-08-27T08:16:18Z",
"content": "text",
"attachment": {
"type": "Document",
"url": "http://pasture-one-actor/images/100.png",
"name": "name",
"summary": "summary",
"content": "content"
}
}
}
gotosocial
{
"id": "01K3GVAS0G0W028RJVD5D7QMF9",
"created_at": "2025-08-25T14:50:18.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/object/OnBrBHlmx20",
"url": "http://pasture-one-actor/object/OnBrBHlmx20",
"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": "01K3GV8459F044M7E2J13WTR56",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-08-25T14:48:51.133Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon5.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon5.png",
"header": "http://gotosocial/assets/default_header.png",
"header_static": "http://gotosocial/assets/default_header.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 34,
"last_status_at": "2025-08-25T14:50:18.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K3GVASNEY5Z8489RGSAK97HM",
"type": "image",
"url": "http://gotosocial/fileserver/01K3GV8459F044M7E2J13WTR56/attachment/original/01K3GVASNEY5Z8489RGSAK97HM.png",
"text_url": "http://gotosocial/fileserver/01K3GV8459F044M7E2J13WTR56/attachment/original/01K3GVASNEY5Z8489RGSAK97HM.png",
"preview_url": "http://gotosocial/fileserver/01K3GV8459F044M7E2J13WTR56/attachment/small/01K3GVASNEY5Z8489RGSAK97HM.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": "L58b*LubfQububkAfQkAfQfQfQfQ"
}
],
"mentions": [
{
"id": "01KA518HV2YMVXQKRA76EF2ZJV",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}
hollo
{
"id": "0198ea99-6450-73eb-b8b5-bb858190bdc7",
"created_at": "2025-08-27T08:16:18.000Z",
"in_reply_to_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/object/z7i5Hs9qisk",
"url": "http://pasture-one-actor/object/z7i5Hs9qisk",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "text",
"reblog": null,
"quote_id": null,
"quote": null,
"application": null,
"account": {
"id": "0198ea98-1daf-74ca-ab5b-29bdfc9e43ad",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": false,
"bot": false,
"created_at": "2025-08-27T08:14:54.323Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://hollo/image/avatars/original/missing.png",
"avatar_static": "http://hollo/image/avatars/original/missing.png",
"header": "http://hollo/image/headers/original/missing.png",
"header_static": "http://hollo/image/headers/original/missing.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 0,
"moved": null,
"last_status_at": null,
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "0198ea99-686d-72cf-bf2e-a74d268c6f06",
"type": "image",
"url": "http://pasture-one-actor/images/100.png",
"preview_url": "http://pasture-one-actor/images/100.png",
"remote_url": null,
"text_url": null,
"meta": {
"original": {
"width": 512,
"height": 512,
"size": "512x512",
"aspect": 1
},
"small": {
"width": 512,
"height": 512,
"size": "512x512",
"aspect": 1
},
"focus": {
"x": 0,
"y": 0
}
},
"description": "summary",
"blurhash": null
}
],
"mentions": [],
"tags": [],
"card": null,
"emojis": [],
"emoji_reactions": [],
"poll": null,
"filtered": 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": [
"http://hollo/@john",
"as:Public"
],
"id": "http://pasture-one-actor/activity/99gcHI0bCPE",
"published": "2025-08-27T08:16:19Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"as:Public",
"http://hollo/@john"
],
"id": "http://pasture-one-actor/object/C7MqhjoAKW0",
"published": "2025-08-27T08:16:19Z",
"content": "text",
"attachment": [
{
"type": "Document",
"url": "http://pasture-one-actor/assets/FediverseLogo.png",
"name": "name",
"imageType": "image/jpeg"
}
]
}
}
gotosocial
{
"id": "01K3GVASZRMB1Q40XZGJSXMGVF",
"created_at": "2025-08-25T14:50:19.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/object/FkyAhUSFyM8",
"url": "http://pasture-one-actor/object/FkyAhUSFyM8",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "text<hr><p><i lang=\"en\">\u2139\ufe0f Note from gotosocial: 1 attachment in this status could not be downloaded. Treat the following external link with care:</i></p><ul><li><a href=\"http://pasture-one-actor/assets/FediverseLogo.png\" rel=\"nofollow noreferrer noopener\" target=\"_blank\">FediverseLogo.png</a> [name]</li></ul>",
"reblog": null,
"account": {
"id": "01K3GV8459F044M7E2J13WTR56",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-08-25T14:48:51.133Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon5.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon5.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": "2025-08-25T14:50:19.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [],
"mentions": [
{
"id": "01KA518HV2YMVXQKRA76EF2ZJV",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}
hollo
{
"id": "0198ea99-6838-793c-a8b0-71c8aa682bbe",
"created_at": "2025-08-27T08:16:19.000Z",
"in_reply_to_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/object/C7MqhjoAKW0",
"url": "http://pasture-one-actor/object/C7MqhjoAKW0",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "text",
"reblog": null,
"quote_id": null,
"quote": null,
"application": null,
"account": {
"id": "0198ea98-1daf-74ca-ab5b-29bdfc9e43ad",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": false,
"bot": false,
"created_at": "2025-08-27T08:14:54.323Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://hollo/image/avatars/original/missing.png",
"avatar_static": "http://hollo/image/avatars/original/missing.png",
"header": "http://hollo/image/headers/original/missing.png",
"header_static": "http://hollo/image/headers/original/missing.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 0,
"moved": null,
"last_status_at": null,
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "0198ea99-6b59-7bf2-b10b-a68d455ad3af",
"type": "text",
"url": "http://pasture-one-actor/assets/FediverseLogo.png",
"preview_url": "http://pasture-one-actor/assets/FediverseLogo.png",
"remote_url": null,
"text_url": null,
"meta": {
"original": {
"width": 512,
"height": 512,
"size": "512x512",
"aspect": 1
},
"small": {
"width": 512,
"height": 512,
"size": "512x512",
"aspect": 1
},
"focus": {
"x": 0,
"y": 0
}
},
"description": "name",
"blurhash": null
}
],
"mentions": [],
"tags": [],
"card": null,
"emojis": [],
"emoji_reactions": [],
"poll": null,
"filtered": 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": [
"http://hollo/@john",
"as:Public"
],
"id": "http://pasture-one-actor/activity/-h8UxUfk4xY",
"published": "2025-08-27T08:16:20Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"as:Public",
"http://hollo/@john"
],
"id": "http://pasture-one-actor/object/Fa60oyuERF8",
"published": "2025-08-27T08:16:20Z",
"content": "no comment in attachment",
"attachment": [
{
"type": "Document",
"url": "http://pasture-one-actor/assets/FediverseLogo.png"
}
]
}
}
gotosocial
{
"id": "01K3GVASZRJM0DCZQC1W704CD2",
"created_at": "2025-08-25T14:50:19.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/object/kkcv8zWRMLo",
"url": "http://pasture-one-actor/object/kkcv8zWRMLo",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "no comment in attachment<hr><p><i lang=\"en\">\u2139\ufe0f Note from gotosocial: 1 attachment in this status could not be downloaded. Treat the following external link with care:</i></p><ul><li><a href=\"http://pasture-one-actor/assets/FediverseLogo.png\" rel=\"nofollow noreferrer noopener\" target=\"_blank\">FediverseLogo.png</a></li></ul>",
"reblog": null,
"account": {
"id": "01K3GV8459F044M7E2J13WTR56",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-08-25T14:48:51.133Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon5.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon5.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": "2025-08-25T14:50:19.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [],
"mentions": [
{
"id": "01KA518HV2YMVXQKRA76EF2ZJV",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}
hollo
{
"id": "0198ea99-6c20-78c4-9ebd-27b53b25149c",
"created_at": "2025-08-27T08:16:20.000Z",
"in_reply_to_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture-one-actor/object/Fa60oyuERF8",
"url": "http://pasture-one-actor/object/Fa60oyuERF8",
"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,
"quote_id": null,
"quote": null,
"application": null,
"account": {
"id": "0198ea98-1daf-74ca-ab5b-29bdfc9e43ad",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": false,
"bot": false,
"created_at": "2025-08-27T08:14:54.323Z",
"note": "",
"url": "http://pasture-one-actor/actor",
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