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://gotosocial/users/cookie",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/nvqJ6ndne68",
"published": "2025-10-11T09:25:39Z",
"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/2OpZP8qla_g",
"published": "2025-10-11T09:25:39Z",
"content": "no description",
"attachment": {
"type": "Image",
"url": "http://pasture-one-actor/images/ad086e96-90ca-4c40-b3fa-4d4fe233dddd.png"
},
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K799E3HR2EW0WYYXQF8VK8YY",
"created_at": "2025-10-11T09:25:39.000Z",
"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/2OpZP8qla_g",
"url": "http://pasture-one-actor/object/2OpZP8qla_g",
"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": "01K799AVRQHSQ0QTMSD7B7MVJE",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-10-11T09:23:52.739Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.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": "2025-10-11T09:25:39.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K799E3SMS6H1D151QBNKQP6Y",
"type": "image",
"url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E3SMS6H1D151QBNKQP6Y.png",
"text_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E3SMS6H1D151QBNKQP6Y.png",
"preview_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/small/01K799E3SMS6H1D151QBNKQP6Y.jpg",
"remote_url": "http://pasture-one-actor/images/ad086e96-90ca-4c40-b3fa-4d4fe233dddd.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": "L6N[_:~8fQ~8~8oLfQoLfQfQfQfQ"
}
],
"mentions": [
{
"id": "01KMNPWBHK63MF9V23XHFA4TTA",
"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": [
"http://gotosocial/users/cookie",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/H1aDq5n7o0s",
"published": "2025-10-11T09:25:39Z",
"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/IjvvPq4OfBw",
"published": "2025-10-11T09:25:39Z",
"content": "name, summary and content",
"attachment": {
"type": "Image",
"url": "http://pasture-one-actor/images/14162f51-a8f9-4ae7-ad48-3627168209dc.png",
"name": "name",
"summary": "summary",
"content": "content"
},
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K799E3HRA705VXNH6CGT6XDR",
"created_at": "2025-10-11T09:25:39.000Z",
"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/IjvvPq4OfBw",
"url": "http://pasture-one-actor/object/IjvvPq4OfBw",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "name, summary and content",
"reblog": null,
"account": {
"id": "01K799AVRQHSQ0QTMSD7B7MVJE",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-10-11T09:23:52.739Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.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": "2025-10-11T09:25:39.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K799E4BDBYJTQGX9SPJMEVAJ",
"type": "image",
"url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E4BDBYJTQGX9SPJMEVAJ.png",
"text_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E4BDBYJTQGX9SPJMEVAJ.png",
"preview_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/small/01K799E4BDBYJTQGX9SPJMEVAJ.jpg",
"remote_url": "http://pasture-one-actor/images/14162f51-a8f9-4ae7-ad48-3627168209dc.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": "L8NU?W??fQ????kBfQkBfQfQfQfQ"
}
],
"mentions": [
{
"id": "01KMNPWBHK63MF9V23XHFA4TTA",
"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": [
"http://gotosocial/users/cookie",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/SSHBSkDjejI",
"published": "2025-10-11T09:25:40Z",
"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/myKJPz3pqVI",
"published": "2025-10-11T09:25:40Z",
"content": "only name",
"attachment": [
{
"type": "Image",
"url": "http://pasture-one-actor/assets/FediverseLogo.png",
"name": "name",
"imageType": "image/jpeg"
}
],
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K799E4H0S5KTM7VEEM26SDX7",
"created_at": "2025-10-11T09:25:40.000Z",
"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/myKJPz3pqVI",
"url": "http://pasture-one-actor/object/myKJPz3pqVI",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "only name",
"reblog": null,
"account": {
"id": "01K799AVRQHSQ0QTMSD7B7MVJE",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-10-11T09:23:52.739Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.png",
"header": "http://gotosocial/assets/default_header.png",
"header_static": "http://gotosocial/assets/default_header.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 77,
"last_status_at": "2025-10-11T09:25:40.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K799E4XN49XH581B2GWMMRE4",
"type": "image",
"url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E4XN49XH581B2GWMMRE4.png",
"text_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E4XN49XH581B2GWMMRE4.png",
"preview_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/small/01K799E4XN49XH581B2GWMMRE4.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": "01KMNPWBHK63MF9V23XHFA4TTA",
"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": [
"http://gotosocial/users/cookie",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/TsOhJlZpp60",
"published": "2025-10-11T09:25:40Z",
"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/KygKIhCeemI",
"published": "2025-10-11T09:25:40Z",
"content": "only summary",
"attachment": {
"type": "Image",
"url": "http://pasture-one-actor/images/fa6e08cb-2c50-407a-87dc-a5518f598893.png",
"name": "name",
"summary": "summary",
"content": "content"
},
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K799E4H0B0C3K7HHFGJFFSDS",
"created_at": "2025-10-11T09:25:40.000Z",
"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/KygKIhCeemI",
"url": "http://pasture-one-actor/object/KygKIhCeemI",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "only summary",
"reblog": null,
"account": {
"id": "01K799AVRQHSQ0QTMSD7B7MVJE",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-10-11T09:23:52.739Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.png",
"header": "http://gotosocial/assets/default_header.png",
"header_static": "http://gotosocial/assets/default_header.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 78,
"last_status_at": "2025-10-11T09:25:40.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K799E5FFTGBX08DPQ25BKYY6",
"type": "image",
"url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E5FFTGBX08DPQ25BKYY6.png",
"text_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E5FFTGBX08DPQ25BKYY6.png",
"preview_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/small/01K799E5FFTGBX08DPQ25BKYY6.jpg",
"remote_url": "http://pasture-one-actor/images/fa6e08cb-2c50-407a-87dc-a5518f598893.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": "L8JU6f.kfQ.k.kkBfQkBfQfQfQfQ"
}
],
"mentions": [
{
"id": "01KMNPWBHK63MF9V23XHFA4TTA",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}
Example 5¶
activity
{
"@context": [
"https://www.w3.org/ns/activitystreams",
{
"Hashtag": "as:Hashtag",
"sensitive": "as:sensitive"
}
],
"type": "Create",
"actor": "http://pasture-one-actor/actor",
"to": [
"http://gotosocial/users/cookie",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/ixur9mUzY30",
"published": "2025-10-11T09:25:41Z",
"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/bBNgj6scCCw",
"published": "2025-10-11T09:25:41Z",
"content": "only content",
"attachment": {
"type": "Image",
"url": "http://pasture-one-actor/images/53a5305d-816f-4d7d-b231-5da1534b151d.png",
"content": "content"
},
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
{
"id": "01K799E5G84B3VM8QYVA17VSDF",
"created_at": "2025-10-11T09:25:41.000Z",
"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/bBNgj6scCCw",
"url": "http://pasture-one-actor/object/bBNgj6scCCw",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"pinned": false,
"content": "only content",
"reblog": null,
"account": {
"id": "01K799AVRQHSQ0QTMSD7B7MVJE",
"username": "actor",
"acct": "actor@pasture-one-actor",
"display_name": "Test Actor",
"locked": true,
"discoverable": false,
"bot": false,
"created_at": "2025-10-11T09:23:52.739Z",
"note": "",
"url": "http://pasture-one-actor/actor",
"avatar": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.png",
"avatar_static": "http://gotosocial/assets/default_avatars/GoToSocial_icon6.png",
"header": "http://gotosocial/assets/default_header.png",
"header_static": "http://gotosocial/assets/default_header.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 79,
"last_status_at": "2025-10-11T09:25:41.000Z",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "01K799E619CSJAR7SW6V30Z3ZM",
"type": "image",
"url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E619CSJAR7SW6V30Z3ZM.png",
"text_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/original/01K799E619CSJAR7SW6V30Z3ZM.png",
"preview_url": "http://gotosocial/fileserver/01K799AVRQHSQ0QTMSD7B7MVJE/attachment/small/01K799E619CSJAR7SW6V30Z3ZM.jpg",
"remote_url": "http://pasture-one-actor/images/53a5305d-816f-4d7d-b231-5da1534b151d.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": "L5Naaa}pfQ}p}poKfQoKfQfQfQfQ"
}
],
"mentions": [
{
"id": "01KMNPWBHK63MF9V23XHFA4TTA",
"username": "cookie",
"url": "http://gotosocial/@cookie",
"acct": "cookie"
}
],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}
Example 6¶
activity
{
"@context": [
"https://www.w3.org/ns/activitystreams",
{
"Hashtag": "as:Hashtag",
"sensitive": "as:sensitive"
}
],
"type": "Create",
"actor": "http://pasture-one-actor/actor",
"to": [
"http://gotosocial/users/cookie",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture-one-actor/activity/PTRvp2wA27M",
"published": "2025-10-11T09:25:42Z",
"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/gaqqfo3gV_I",
"published": "2025-10-11T09:25:42Z",
"content": "no comment in attachment; reused image",
"attachment": [
{
"type": "Image",
"url": "http://pasture-one-actor/assets/FediverseLogo.png"
}
],
"tag": [
{
"type": "Mention",
"href": "http://gotosocial/users/cookie"
}
]
}
}
gotosocial
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