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. misskey, 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://mitra/users/admin",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/XTEBeYngwoc",
"published": "2025-09-26T07:49:12Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mitra/users/admin"
],
"id": "http://pasture-one-actor/object/6-S_thydQlU",
"published": "2025-09-26T07:49:12Z",
"content": "no description",
"attachment": {
"type": "Document",
"url": "http://pasture-one-actor/images/100.png"
}
}
}
mitra
{
"id": "019984ff-60f3-1a06-30dd-1ea48ca8e93d",
"uri": "http://pasture-one-actor/object/6-S_thydQlU",
"url": "http://pasture-one-actor/object/6-S_thydQlU",
"created_at": "2025-09-26T07:49:12.000Z",
"edited_at": null,
"account": {
"id": "019984fc-fdfa-dbbd-a6a5-29b8e88962b0",
"username": "actor",
"acct": "actor@pasture-one-actor",
"actor_id": "http://pasture-one-actor/actor",
"url": "http://pasture-one-actor/actor",
"display_name": "Test Actor",
"created_at": "2025-09-26T07:46:36.666Z",
"note": "",
"avatar": "http://mitra/api/v1/accounts/identicon?input=http://pasture-one-actor/actor",
"header": "http://mitra/api/v1/accounts/identicon",
"locked": false,
"mention_policy": "none",
"bot": false,
"identity_proofs": [],
"payment_options": [],
"fields": [],
"emojis": [],
"followers_count": 0,
"following_count": 0,
"subscribers_count": 0,
"statuses_count": 69,
"source": null,
"role": null,
"authentication_methods": null,
"client_config": null
},
"content": "no description",
"language": null,
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"reblog": null,
"visibility": "public",
"sensitive": false,
"spoiler_text": "",
"pinned": false,
"replies_count": 0,
"favourites_count": 0,
"reblogs_count": 0,
"poll": null,
"media_attachments": [
{
"id": "019984ff-60ef-704e-45b6-59c3f188224d",
"type": "image",
"url": "http://mitra/media/e83a5a454c34948897ba61ae7cb501dcf1e39d0094eb4dc158d9fd1e36c347d9.png",
"preview_url": "http://mitra/media/e83a5a454c34948897ba61ae7cb501dcf1e39d0094eb4dc158d9fd1e36c347d9.png",
"description": null
}
],
"quote": null,
"mentions": [
{
"id": "019984fb-bee8-fd54-f1c4-53cd53d52fe7",
"username": "admin",
"acct": "admin",
"url": "http://mitra/users/admin"
}
],
"tags": [],
"emojis": [],
"favourited": false,
"reblogged": false,
"bookmarked": false,
"pleroma": {
"emoji_reactions": [],
"in_reply_to_account_acct": null,
"parent_visible": true,
"quote": null,
"quote_visible": true
},
"hidden": false,
"ipfs_cid": null,
"links": []
}
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://mitra/users/admin",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/L8x417OX_9s",
"published": "2025-09-26T07:49:13Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mitra/users/admin"
],
"id": "http://pasture-one-actor/object/bGahKiA5v7s",
"published": "2025-09-26T07:49:13Z",
"content": "name and summary",
"attachment": {
"type": "Document",
"url": "http://pasture-one-actor/images/100.png",
"name": "name",
"summary": "summary",
"content": "content"
}
}
}
mitra
{
"id": "019984ff-66da-7322-24b9-b199dbab8cd3",
"uri": "http://pasture-one-actor/object/bGahKiA5v7s",
"url": "http://pasture-one-actor/object/bGahKiA5v7s",
"created_at": "2025-09-26T07:49:13.000Z",
"edited_at": null,
"account": {
"id": "019984fc-fdfa-dbbd-a6a5-29b8e88962b0",
"username": "actor",
"acct": "actor@pasture-one-actor",
"actor_id": "http://pasture-one-actor/actor",
"url": "http://pasture-one-actor/actor",
"display_name": "Test Actor",
"created_at": "2025-09-26T07:46:36.666Z",
"note": "",
"avatar": "http://mitra/api/v1/accounts/identicon?input=http://pasture-one-actor/actor",
"header": "http://mitra/api/v1/accounts/identicon",
"locked": false,
"mention_policy": "none",
"bot": false,
"identity_proofs": [],
"payment_options": [],
"fields": [],
"emojis": [],
"followers_count": 0,
"following_count": 0,
"subscribers_count": 0,
"statuses_count": 70,
"source": null,
"role": null,
"authentication_methods": null,
"client_config": null
},
"content": "name and summary",
"language": null,
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"reblog": null,
"visibility": "public",
"sensitive": false,
"spoiler_text": "",
"pinned": false,
"replies_count": 0,
"favourites_count": 0,
"reblogs_count": 0,
"poll": null,
"media_attachments": [
{
"id": "019984ff-66d6-7ff5-5fb2-f3297bbd0d0f",
"type": "image",
"url": "http://mitra/media/e3c701b6195070c3b404e0d2c6aa0064558cf61797f480802027613ff649da33.png",
"preview_url": "http://mitra/media/e3c701b6195070c3b404e0d2c6aa0064558cf61797f480802027613ff649da33.png",
"description": "name"
}
],
"quote": null,
"mentions": [
{
"id": "019984fb-bee8-fd54-f1c4-53cd53d52fe7",
"username": "admin",
"acct": "admin",
"url": "http://mitra/users/admin"
}
],
"tags": [],
"emojis": [],
"favourited": false,
"reblogged": false,
"bookmarked": false,
"pleroma": {
"emoji_reactions": [],
"in_reply_to_account_acct": null,
"parent_visible": true,
"quote": null,
"quote_visible": true
},
"hidden": false,
"ipfs_cid": null,
"links": []
}
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://mitra/users/admin",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/q0_Q9wYgczU",
"published": "2025-09-26T07:49:14Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mitra/users/admin"
],
"id": "http://pasture-one-actor/object/QB5nP23C1y4",
"published": "2025-09-26T07:49:14Z",
"content": "only name",
"attachment": [
{
"type": "Document",
"url": "http://pasture-one-actor/assets/FediverseLogo.png",
"name": "name",
"imageType": "image/jpeg"
}
]
}
}
mitra
{
"id": "019984ff-6cba-d70b-ce08-ed2417d9f49a",
"uri": "http://pasture-one-actor/object/QB5nP23C1y4",
"url": "http://pasture-one-actor/object/QB5nP23C1y4",
"created_at": "2025-09-26T07:49:14.000Z",
"edited_at": null,
"account": {
"id": "019984fc-fdfa-dbbd-a6a5-29b8e88962b0",
"username": "actor",
"acct": "actor@pasture-one-actor",
"actor_id": "http://pasture-one-actor/actor",
"url": "http://pasture-one-actor/actor",
"display_name": "Test Actor",
"created_at": "2025-09-26T07:46:36.666Z",
"note": "",
"avatar": "http://mitra/api/v1/accounts/identicon?input=http://pasture-one-actor/actor",
"header": "http://mitra/api/v1/accounts/identicon",
"locked": false,
"mention_policy": "none",
"bot": false,
"identity_proofs": [],
"payment_options": [],
"fields": [],
"emojis": [],
"followers_count": 0,
"following_count": 0,
"subscribers_count": 0,
"statuses_count": 71,
"source": null,
"role": null,
"authentication_methods": null,
"client_config": null
},
"content": "only name",
"language": null,
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"reblog": null,
"visibility": "public",
"sensitive": false,
"spoiler_text": "",
"pinned": false,
"replies_count": 0,
"favourites_count": 0,
"reblogs_count": 0,
"poll": null,
"media_attachments": [
{
"id": "019984ff-6cb7-17c7-6f6e-5e9e138d5577",
"type": "image",
"url": "http://mitra/media/2d7a61d31393a44edf2a30160cdd70b3582a4f97d5b550f8141dfee1641b4ae7.png",
"preview_url": "http://mitra/media/2d7a61d31393a44edf2a30160cdd70b3582a4f97d5b550f8141dfee1641b4ae7.png",
"description": "name"
}
],
"quote": null,
"mentions": [
{
"id": "019984fb-bee8-fd54-f1c4-53cd53d52fe7",
"username": "admin",
"acct": "admin",
"url": "http://mitra/users/admin"
}
],
"tags": [],
"emojis": [],
"favourited": false,
"reblogged": false,
"bookmarked": false,
"pleroma": {
"emoji_reactions": [],
"in_reply_to_account_acct": null,
"parent_visible": true,
"quote": null,
"quote_visible": true
},
"hidden": false,
"ipfs_cid": null,
"links": []
}
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://mitra/users/admin",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/ElyPCBu3PwE",
"published": "2025-09-26T07:49:16Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mitra/users/admin"
],
"id": "http://pasture-one-actor/object/MAsUPeemJ2Q",
"published": "2025-09-26T07:49:16Z",
"content": "no comment in attachment",
"attachment": [
{
"type": "Document",
"url": "http://pasture-one-actor/assets/FediverseLogo.png"
}
]
}
}
mitra
{
"id": "019984ff-7293-6883-dcf6-c46af765cce4",
"uri": "http://pasture-one-actor/object/MAsUPeemJ2Q",
"url": "http://pasture-one-actor/object/MAsUPeemJ2Q",
"created_at": "2025-09-26T07:49:16.000Z",
"edited_at": null,
"account": {
"id": "019984fc-fdfa-dbbd-a6a5-29b8e88962b0",
"username": "actor",
"acct": "actor@pasture-one-actor",
"actor_id": "http://pasture-one-actor/actor",
"url": "http://pasture-one-actor/actor",
"display_name": "Test Actor",
"created_at": "2025-09-26T07:46:36.666Z",
"note": "",
"avatar": "http://mitra/api/v1/accounts/identicon?input=http://pasture-one-actor/actor",
"header": "http://mitra/api/v1/accounts/identicon",
"locked": false,
"mention_policy": "none",
"bot": false,
"identity_proofs": [],
"payment_options": [],
"fields": [],
"emojis": [],
"followers_count": 0,
"following_count": 0,
"subscribers_count": 0,
"statuses_count": 72,
"source": null,
"role": null,
"authentication_methods": null,
"client_config": null
},
"content": "no comment in attachment",
"language": null,
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"reblog": null,
"visibility": "public",
"sensitive": false,
"spoiler_text": "",
"pinned": false,
"replies_count": 0,
"favourites_count": 0,
"reblogs_count": 0,
"poll": null,
"media_attachments": [
{
"id": "019984ff-7290-c87a-1ef4-66e5d411365a",
"type": "image",
"url": "http://mitra/media/2d7a61d31393a44edf2a30160cdd70b3582a4f97d5b550f8141dfee1641b4ae7.png",
"preview_url": "http://mitra/media/2d7a61d31393a44edf2a30160cdd70b3582a4f97d5b550f8141dfee1641b4ae7.png",
"description": null
}
],
"quote": null,
"mentions": [
{
"id": "019984fb-bee8-fd54-f1c4-53cd53d52fe7",
"username": "admin",
"acct": "admin",
"url": "http://mitra/users/admin"
}
],
"tags": [],
"emojis": [],
"favourited": false,
"reblogged": false,
"bookmarked": false,
"pleroma": {
"emoji_reactions": [],
"in_reply_to_account_acct": null,
"parent_visible": true,
"quote": null,
"quote_visible": true
},
"hidden": false,
"ipfs_cid": null,
"links": []
}
Example 5¶
no result
no result
Example 6¶
no result
no result