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://mastodon/users/hippo",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture_one_actor/actor/lalQo4pgEI0",
"object": {
"type": "Note",
"attributedTo": "http://pasture_one_actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mastodon/users/hippo"
],
"id": "http://pasture_one_actor/actor/z2XFaG-X0_c",
"published": "2024-03-01T11:51:20Z",
"content": "no description",
"attachment": {
"type": "Document",
"url": "http://pasture_one_actor/images/100.png"
}
}
}
mastodon
{
"id": "112020283743848478",
"created_at": "2024-03-01T11:51:20.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture_one_actor/actor/z2XFaG-X0_c",
"url": "http://pasture_one_actor/actor/z2XFaG-X0_c",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"edited_at": null,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"content": "no description",
"filtered": [],
"reblog": null,
"account": {
"id": "112020279142740277",
"username": "actor",
"acct": "actor@pasture_one_actor",
"display_name": "Test Actor",
"locked": false,
"bot": false,
"discoverable": false,
"group": false,
"created_at": "2024-03-01T00:00:00.000Z",
"note": "",
"url": "http://pasture_one_actor/actor",
"avatar": "http://mastodon/avatars/original/missing.png",
"avatar_static": "http://mastodon/avatars/original/missing.png",
"header": "http://mastodon/headers/original/missing.png",
"header_static": "http://mastodon/headers/original/missing.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 29,
"last_status_at": "2024-03-01",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "112020283740094301",
"type": "image",
"url": "http://mastodon/system/cache/media_attachments/files/112/020/283/740/094/301/original/963884b8a4dfcfb7.png",
"preview_url": "http://mastodon/system/cache/media_attachments/files/112/020/283/740/094/301/small/963884b8a4dfcfb7.png",
"remote_url": "http://pasture_one_actor/images/100.png",
"preview_remote_url": null,
"text_url": null,
"meta": {
"original": {
"width": 40,
"height": 40,
"size": "40x40",
"aspect": 1.0
},
"small": {
"width": 40,
"height": 40,
"size": "40x40",
"aspect": 1.0
}
},
"description": null,
"blurhash": "U18q].%jfQ%j%jj]fQj]fQfQfQfQ%jj]fQj]"
}
],
"mentions": [],
"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://mastodon/users/hippo",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture_one_actor/actor/evFthm7pA_U",
"object": {
"type": "Note",
"attributedTo": "http://pasture_one_actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mastodon/users/hippo"
],
"id": "http://pasture_one_actor/actor/rxA_WFUZf0g",
"published": "2024-03-01T11:51:22Z",
"content": "text",
"attachment": {
"type": "Document",
"url": "http://pasture_one_actor/images/100.png",
"name": "name",
"summary": "summary",
"content": "content"
}
}
}
mastodon
{
"id": "112020283905634174",
"created_at": "2024-03-01T11:51:22.000Z",
"in_reply_to_id": null,
"in_reply_to_account_id": null,
"sensitive": false,
"spoiler_text": "",
"visibility": "public",
"language": null,
"uri": "http://pasture_one_actor/actor/rxA_WFUZf0g",
"url": "http://pasture_one_actor/actor/rxA_WFUZf0g",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"edited_at": null,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"content": "text",
"filtered": [],
"reblog": null,
"account": {
"id": "112020279142740277",
"username": "actor",
"acct": "actor@pasture_one_actor",
"display_name": "Test Actor",
"locked": false,
"bot": false,
"discoverable": false,
"group": false,
"created_at": "2024-03-01T00:00:00.000Z",
"note": "",
"url": "http://pasture_one_actor/actor",
"avatar": "http://mastodon/avatars/original/missing.png",
"avatar_static": "http://mastodon/avatars/original/missing.png",
"header": "http://mastodon/headers/original/missing.png",
"header_static": "http://mastodon/headers/original/missing.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 30,
"last_status_at": "2024-03-01",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "112020283902438617",
"type": "image",
"url": "http://mastodon/system/cache/media_attachments/files/112/020/283/902/438/617/original/509fbab893689012.png",
"preview_url": "http://mastodon/system/cache/media_attachments/files/112/020/283/902/438/617/small/509fbab893689012.png",
"remote_url": "http://pasture_one_actor/images/100.png",
"preview_remote_url": null,
"text_url": null,
"meta": {
"original": {
"width": 40,
"height": 40,
"size": "40x40",
"aspect": 1.0
},
"small": {
"width": 40,
"height": 40,
"size": "40x40",
"aspect": 1.0
}
},
"description": "summary",
"blurhash": "U7H~au*HfQ*H*Hj[fQj[fQfQfQfQ*Hj[fQj["
}
],
"mentions": [],
"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://mastodon/users/hippo",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture_one_actor/actor/kSo2J1TCvgM",
"object": {
"type": "Note",
"attributedTo": "http://pasture_one_actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mastodon/users/hippo"
],
"id": "http://pasture_one_actor/actor/n3MBL-XyHoM",
"published": "2024-03-01T11:51:25Z",
"content": "text",
"attachment": [
{
"type": "Document",
"url": "http://pasture_one_actor/assets/FediverseLogo.png",
"name": "name",
"imageType": "image/jpeg"
}
]
}
}
mastodon
{
"id": "112020284130326826",
"created_at": "2024-03-01T11:51:25.000Z",
"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/n3MBL-XyHoM",
"url": "http://pasture_one_actor/actor/n3MBL-XyHoM",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"edited_at": null,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"content": "text",
"filtered": [],
"reblog": null,
"account": {
"id": "112020279142740277",
"username": "actor",
"acct": "actor@pasture_one_actor",
"display_name": "Test Actor",
"locked": false,
"bot": false,
"discoverable": false,
"group": false,
"created_at": "2024-03-01T00:00:00.000Z",
"note": "",
"url": "http://pasture_one_actor/actor",
"avatar": "http://mastodon/avatars/original/missing.png",
"avatar_static": "http://mastodon/avatars/original/missing.png",
"header": "http://mastodon/headers/original/missing.png",
"header_static": "http://mastodon/headers/original/missing.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 31,
"last_status_at": "2024-03-01",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "112020284068164963",
"type": "image",
"url": "http://mastodon/system/cache/media_attachments/files/112/020/284/068/164/963/original/0cb8817e708fd738.png",
"preview_url": "http://mastodon/system/cache/media_attachments/files/112/020/284/068/164/963/small/0cb8817e708fd738.png",
"remote_url": "http://pasture_one_actor/assets/FediverseLogo.png",
"preview_remote_url": null,
"text_url": null,
"meta": {
"original": {
"width": 1440,
"height": 1440,
"size": "1440x1440",
"aspect": 1.0
},
"small": {
"width": 480,
"height": 480,
"size": "480x480",
"aspect": 1.0
}
},
"description": "name",
"blurhash": "UJC$ci*q55T?}fjFEVw[4?K[RT$l9,O?V?X2"
}
],
"mentions": [],
"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://mastodon/users/hippo",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "http://pasture_one_actor/actor/40M58scqxbc",
"object": {
"type": "Note",
"attributedTo": "http://pasture_one_actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mastodon/users/hippo"
],
"id": "http://pasture_one_actor/actor/F3qG6Q1XzDU",
"published": "2024-03-01T11:51:27Z",
"content": "no comment in attachment",
"attachment": [
{
"type": "Document",
"url": "http://pasture_one_actor/assets/FediverseLogo.png"
}
]
}
}
mastodon
{
"id": "112020284295365158",
"created_at": "2024-03-01T11:51:27.000Z",
"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/F3qG6Q1XzDU",
"url": "http://pasture_one_actor/actor/F3qG6Q1XzDU",
"replies_count": 0,
"reblogs_count": 0,
"favourites_count": 0,
"edited_at": null,
"favourited": false,
"reblogged": false,
"muted": false,
"bookmarked": false,
"content": "no comment in attachment",
"filtered": [],
"reblog": null,
"account": {
"id": "112020279142740277",
"username": "actor",
"acct": "actor@pasture_one_actor",
"display_name": "Test Actor",
"locked": false,
"bot": false,
"discoverable": false,
"group": false,
"created_at": "2024-03-01T00:00:00.000Z",
"note": "",
"url": "http://pasture_one_actor/actor",
"avatar": "http://mastodon/avatars/original/missing.png",
"avatar_static": "http://mastodon/avatars/original/missing.png",
"header": "http://mastodon/headers/original/missing.png",
"header_static": "http://mastodon/headers/original/missing.png",
"followers_count": 0,
"following_count": 0,
"statuses_count": 32,
"last_status_at": "2024-03-01",
"emojis": [],
"fields": []
},
"media_attachments": [
{
"id": "112020284230370172",
"type": "image",
"url": "http://mastodon/system/cache/media_attachments/files/112/020/284/230/370/172/original/84829d50b9accd5e.png",
"preview_url": "http://mastodon/system/cache/media_attachments/files/112/020/284/230/370/172/small/84829d50b9accd5e.png",
"remote_url": "http://pasture_one_actor/assets/FediverseLogo.png",
"preview_remote_url": null,
"text_url": null,
"meta": {
"original": {
"width": 1440,
"height": 1440,
"size": "1440x1440",
"aspect": 1.0
},
"small": {
"width": 480,
"height": 480,
"size": "480x480",
"aspect": 1.0
}
},
"description": null,
"blurhash": "UJC$ci*q55T?}fjFEVw[4?K[RT$l9,O?V?X2"
}
],
"mentions": [],
"tags": [],
"emojis": [],
"card": null,
"poll": null
}