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": [
"https://www.w3.org/ns/activitystreams#Public",
"http://gotosocial/users/cookie"
],
"id": "http://pasture-one-actor/activity/SoT7Etx6c8k",
"published": "2025-09-06T13:19:20Z",
"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/object/9exROrDbWKg",
"published": "2025-09-06T13:19:20Z",
"content": "no description",
"attachment": {
"type": "Document",
"url": "http://pasture-one-actor/images/100.png"
},
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K4FJWTY00VRTE3KSWFAH29D5",
"created_at": "2025-09-06T13:19:20.000Z",
"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/9exROrDbWKg",
"url": "http://pasture-one-actor/object/9exROrDbWKg",
"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": "01K4FJSETK0FS940FPRWEABH14",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-09-06T13:17:29.311Z",
"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": 73,
"last_status_at": "2025-09-06T13:19:20.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K4FJWVJ95AFGG3ESBJC69BWA",
"type": "image",
"url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/original/01K4FJWVJ95AFGG3ESBJC69BWA.png",
"text_url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/original/01K4FJWVJ95AFGG3ESBJC69BWA.png",
"preview_url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/small/01K4FJWVJ95AFGG3ESBJC69BWA.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": "L2HRb.}DfQ}D}DoKfQoKfQfQfQfQ"
}
],
"mentions": [
{
"id": "01MGBGEF2AAH8AGFWQ8MCA8WK5",
"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/activity/e8L0KxojI5s",
"published": "2025-09-06T13:19:21Z",
"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/object/ucjg0dBKROs",
"published": "2025-09-06T13:19:21Z",
"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": "01K4FJWVX8NG455MFBM5DA9NHR",
"created_at": "2025-09-06T13:19:21.000Z",
"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/ucjg0dBKROs",
"url": "http://pasture-one-actor/object/ucjg0dBKROs",
"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": "01K4FJSETK0FS940FPRWEABH14",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-09-06T13:17:29.311Z",
"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": 74,
"last_status_at": "2025-09-06T13:19:21.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K4FJWW77EMBTJR8WJ99EAH70",
"type": "image",
"url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/original/01K4FJWW77EMBTJR8WJ99EAH70.png",
"text_url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/original/01K4FJWW77EMBTJR8WJ99EAH70.png",
"preview_url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/small/01K4FJWW77EMBTJR8WJ99EAH70.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": "L40+vbj%fQj%j%fSfQfSfQfQfQfQ"
}
],
"mentions": [
{
"id": "01MGBGEF2AAH8AGFWQ8MCA8WK5",
"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/activity/4LykfB1x_NE",
"published": "2025-09-06T13:19:21Z",
"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/object/RnmEB-NHw0g",
"published": "2025-09-06T13:19:21Z",
"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": "01K4FJWVX8BZF1A5ZG9YEYE7D8",
"created_at": "2025-09-06T13:19:21.000Z",
"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/RnmEB-NHw0g",
"url": "http://pasture-one-actor/object/RnmEB-NHw0g",
"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": "01K4FJSETK0FS940FPRWEABH14",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-09-06T13:17:29.311Z",
"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": 75,
"last_status_at": "2025-09-06T13:19:21.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K4FJWWVSWN6BF2Y069FFATZ2",
"type": "image",
"url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/original/01K4FJWWVSWN6BF2Y069FFATZ2.png",
"text_url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/original/01K4FJWWVSWN6BF2Y069FFATZ2.png",
"preview_url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/small/01K4FJWWVSWN6BF2Y069FFATZ2.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": "01MGBGEF2AAH8AGFWQ8MCA8WK5",
"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/activity/4va8IVFk96g",
"published": "2025-09-06T13:19:22Z",
"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/object/LaWNXccacf4",
"published": "2025-09-06T13:19:22Z",
"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": "01K4FJWWWG0HD4KHDYDS2GVGFJ",
"created_at": "2025-09-06T13:19:22.000Z",
"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/LaWNXccacf4",
"url": "http://pasture-one-actor/object/LaWNXccacf4",
"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": "01K4FJSETK0FS940FPRWEABH14",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-09-06T13:17:29.311Z",
"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": 76,
"last_status_at": "2025-09-06T13:19:22.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K4FJWXGQRXMQB1QD0TGCNH50",
"type": "image",
"url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/original/01K4FJWXGQRXMQB1QD0TGCNH50.png",
"text_url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/original/01K4FJWXGQRXMQB1QD0TGCNH50.png",
"preview_url": "http://gotosocial/fileserver/01K4FJSETK0FS940FPRWEABH14/attachment/small/01K4FJWXGQRXMQB1QD0TGCNH50.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": "01MGBGEF2AAH8AGFWQ8MCA8WK5",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}