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://mbin/u/oscar"
],
"id": "http://pasture-one-actor/activity/Xa4E_5f3npo",
"published": "2025-10-04T14:44:32Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mbin/u/oscar"
],
"id": "http://pasture-one-actor/object/gpteodKZjvs",
"published": "2025-10-04T14:44:32Z",
"content": "no description",
"attachment": {
"type": "Image",
"url": "http://pasture-one-actor/images/f9531a39-0c37-4a16-8565-266ce26379bc.png"
},
"cc": []
}
}
no result
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://mbin/u/oscar"
],
"id": "http://pasture-one-actor/activity/4hjAlXkO-ys",
"published": "2025-10-04T14:44:45Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mbin/u/oscar"
],
"id": "http://pasture-one-actor/object/psVpOUEmjNo",
"published": "2025-10-04T14:44:45Z",
"content": "name, summary and content",
"attachment": {
"type": "Image",
"url": "http://pasture-one-actor/images/657ce374-661d-4e52-aef9-f32660e1cd59.png",
"name": "name",
"summary": "summary",
"content": "content"
},
"cc": []
}
}
no result
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://mbin/u/oscar"
],
"id": "http://pasture-one-actor/activity/Ja7zkBb93dg",
"published": "2025-10-04T14:44:59Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mbin/u/oscar"
],
"id": "http://pasture-one-actor/object/CM9qM3OpGQk",
"published": "2025-10-04T14:44:59Z",
"content": "only name",
"attachment": [
{
"type": "Image",
"url": "http://pasture-one-actor/assets/FediverseLogo.png",
"name": "name",
"imageType": "image/jpeg"
}
],
"cc": []
}
}
mbin
{
"content": "<div class=\"content\">\n<p>only name</p>\n</div>",
"html": "<blockquote class=\"section post subject\" data-action=\"notifications:Notification@window->subject#notification\" data-controller=\"post subject mentions html-refresh\" id=\"post-61\">\n<header>\n<a class=\"user-inline\" data-action=\"mouseover->mentions#user_popup mouseout->mentions#user_popup_out\" data-mentions-username-param=\"@actor@pasture-one-actor\" href=\"/u/@actor@pasture-one-actor\" title=\"@actor@pasture-one-actor\">\n actor <i aria-description=\"This user is new (active for less than 30 days)\" class=\"fa-solid fa-leaf new-user-icon\" title=\"This user is new (active for less than 30 days)\"></i>\n</a>\n<span>, </span>\n<a class=\"link-muted\" href=\"/m/random/p/61/only-name\"><time class=\"timeago\" datetime=\"2025-10-04T14:44:59+00:00\" title=\"2025-10-04T14:44:59+00:00\">2 seconds ago \n</time></a>\n</header>\n<figure>\n<a data-action=\"mouseover->mentions#user_popup mouseout->mentions#user_popup_out\" data-mentions-username-param=\"actor@pasture-one-actor\" href=\"/u/@actor@pasture-one-actor\">\n<div class=\"no-avatar\"></div>\n</a>\n</figure>\n<div class=\"content\">\n<p>only name</p>\n</div>\n<aside class=\"vote\">\n<form action=\"/pf/61?choice=0\" class=\"vote__up\" method=\"post\">\n<button aria-label=\"Favorite\" data-action=\"subject#vote\" title=\"Favorite\" type=\"submit\">\n<span data-subject-target=\"favCounter\">0</span> <span><i aria-hidden=\"true\" class=\"fa-solid fa-arrow-up\"></i></span>\n</button>\n</form>\n</aside>\n<footer>\n<figure>\n<figcaption class=\"hidden glightbox-desc thumb-alt-61-2\">\n name\n </figcaption>\n<div class=\"figure-container\">\n<div class=\"figure-thumb\">\n<a class=\"thumb\" data-description=\".thumb-alt-61-2\" data-gallery=\"post-61\" href=\"https://mbin.domain.tdl/media/2d/7a/2d7a61d31393a44edf2a30160cdd70b3582a4f97d5b550f8141dfee1641b4ae7.png\">\n<img alt=\"name\" loading=\"lazy\" src=\"http://mbin/media/cache/resolve/post_thumb/2d/7a/2d7a61d31393a44edf2a30160cdd70b3582a4f97d5b550f8141dfee1641b4ae7.png\" title=\"name\"/>\n</a>\n</div>\n<div class=\"figure-badge\">\n<div class=\"figure-badge-label\">ALT</div>\n</div>\n</div>\n</figure>\n<menu>\n<li>\n<a class=\"stretched-link\" data-action=\"subject#getForm\" href=\"/m/random/p/61/only-name/reply\">Reply</a>\n</li>\n<li>\n<form action=\"/pb/61\" method=\"post\">\n<button class=\"boost-link stretched-link\" data-action=\"subject#favourite\" type=\"submit\">\n Boost <span class=\"hidden\" data-subject-target=\"upvoteCounter\">(0)</span>\n</button>\n</form>\n</li>\n<li class=\"dropdown\">\n<button class=\"stretched-link\" data-subject-target=\"more\">More</button>\n<ul class=\"dropdown__menu\" data-controller=\"clipboard\">\n<li>\n<a class=\"\" data-action=\"subject#getForm\" href=\"/pr/61\">\n Report\n </a>\n</li>\n<li>\n<a class=\"\" href=\"/m/random/p/61/only-name/votes?type=up\">\n Activity\n </a>\n</li>\n<li class=\"dropdown__separator\"></li>\n<li>\n<a href=\"http://pasture-one-actor/object/CM9qM3OpGQk\" rel=\"nofollow noopener noreferrer\" target=\"_blank\">\n Open original URL\n </a>\n</li>\n<li>\n<a data-action=\"clipboard#copy\" href=\"http://pasture-one-actor/object/CM9qM3OpGQk\" rel=\"nofollow noopener noreferrer\">\n Copy original URL\n </a>\n</li>\n<li>\n<a data-action=\"clipboard#copy\" href=\"/m/random/p/61/only-name\">\n Copy Mbin URL\n </a>\n</li>\n</ul>\n</li>\n<li data-subject-target=\"loader\" style=\"display:none\">\n<div class=\"loader\" role=\"status\">\n<span class=\"visually-hidden\">Loading...</span>\n</div>\n</li>\n</menu>\n<div class=\"js-container\" data-subject-target=\"container\">\n</div>\n</footer>\n</blockquote>"
}
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://mbin/u/oscar"
],
"id": "http://pasture-one-actor/activity/IqbX_K6pfCg",
"published": "2025-10-04T14:45:01Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mbin/u/oscar"
],
"id": "http://pasture-one-actor/object/2Mzb29oFYpk",
"published": "2025-10-04T14:45:01Z",
"content": "only summary",
"attachment": {
"type": "Image",
"url": "http://pasture-one-actor/images/533b2381-2f56-41fc-b85e-5542a00e20a4.png",
"name": "name",
"summary": "summary",
"content": "content"
},
"cc": []
}
}
no result
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": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mbin/u/oscar"
],
"id": "http://pasture-one-actor/activity/6iOeS4zzhtk",
"published": "2025-10-04T14:45:15Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mbin/u/oscar"
],
"id": "http://pasture-one-actor/object/RN6Iqnn4aEs",
"published": "2025-10-04T14:45:15Z",
"content": "only content",
"attachment": {
"type": "Image",
"url": "http://pasture-one-actor/images/44cfb02b-f96f-40c1-8688-4cd6b5fd6a8f.png",
"content": "content"
},
"cc": []
}
}
no result
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": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mbin/u/oscar"
],
"id": "http://pasture-one-actor/activity/YXM7bdWlMu4",
"published": "2025-10-04T14:45:29Z",
"object": {
"type": "Note",
"attributedTo": "http://pasture-one-actor/actor",
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"http://mbin/u/oscar"
],
"id": "http://pasture-one-actor/object/xpwwBk2MP60",
"published": "2025-10-04T14:45:29Z",
"content": "no comment in attachment; reused image",
"attachment": [
{
"type": "Image",
"url": "http://pasture-one-actor/assets/FediverseLogo.png"
}
],
"cc": []
}
}
mbin
{
"content": "<div class=\"content\">\n<p>no comment in attachment; reused image</p>\n</div>",
"html": "<blockquote class=\"section post subject\" data-action=\"notifications:Notification@window->subject#notification\" data-controller=\"post subject mentions html-refresh\" id=\"post-62\">\n<header>\n<a class=\"user-inline\" data-action=\"mouseover->mentions#user_popup mouseout->mentions#user_popup_out\" data-mentions-username-param=\"@actor@pasture-one-actor\" href=\"/u/@actor@pasture-one-actor\" title=\"@actor@pasture-one-actor\">\n actor <i aria-description=\"This user is new (active for less than 30 days)\" class=\"fa-solid fa-leaf new-user-icon\" title=\"This user is new (active for less than 30 days)\"></i>\n</a>\n<span>, </span>\n<a class=\"link-muted\" href=\"/m/random/p/62/no-comment-in-attachment-reused-image\"><time class=\"timeago\" datetime=\"2025-10-04T14:45:29+00:00\" title=\"2025-10-04T14:45:29+00:00\">now \n</time></a>\n</header>\n<figure>\n<a data-action=\"mouseover->mentions#user_popup mouseout->mentions#user_popup_out\" data-mentions-username-param=\"actor@pasture-one-actor\" href=\"/u/@actor@pasture-one-actor\">\n<div class=\"no-avatar\"></div>\n</a>\n</figure>\n<div class=\"content\">\n<p>no comment in attachment; reused image</p>\n</div>\n<aside class=\"vote\">\n<form action=\"/pf/62?choice=0\" class=\"vote__up\" method=\"post\">\n<button aria-label=\"Favorite\" data-action=\"subject#vote\" title=\"Favorite\" type=\"submit\">\n<span data-subject-target=\"favCounter\">0</span> <span><i aria-hidden=\"true\" class=\"fa-solid fa-arrow-up\"></i></span>\n</button>\n</form>\n</aside>\n<footer>\n<figure>\n<figcaption class=\"hidden glightbox-desc thumb-alt-62-2\">\n name\n </figcaption>\n<div class=\"figure-container\">\n<div class=\"figure-thumb\">\n<a class=\"thumb\" data-description=\".thumb-alt-62-2\" data-gallery=\"post-62\" href=\"https://mbin.domain.tdl/media/2d/7a/2d7a61d31393a44edf2a30160cdd70b3582a4f97d5b550f8141dfee1641b4ae7.png\">\n<img alt=\"name\" loading=\"lazy\" src=\"http://mbin/media/cache/resolve/post_thumb/2d/7a/2d7a61d31393a44edf2a30160cdd70b3582a4f97d5b550f8141dfee1641b4ae7.png\" title=\"name\"/>\n</a>\n</div>\n<div class=\"figure-badge\">\n<div class=\"figure-badge-label\">ALT</div>\n</div>\n</div>\n</figure>\n<menu>\n<li>\n<a class=\"stretched-link\" data-action=\"subject#getForm\" href=\"/m/random/p/62/no-comment-in-attachment-reused-image/reply\">Reply</a>\n</li>\n<li>\n<form action=\"/pb/62\" method=\"post\">\n<button class=\"boost-link stretched-link\" data-action=\"subject#favourite\" type=\"submit\">\n Boost <span class=\"hidden\" data-subject-target=\"upvoteCounter\">(0)</span>\n</button>\n</form>\n</li>\n<li class=\"dropdown\">\n<button class=\"stretched-link\" data-subject-target=\"more\">More</button>\n<ul class=\"dropdown__menu\" data-controller=\"clipboard\">\n<li>\n<a class=\"\" data-action=\"subject#getForm\" href=\"/pr/62\">\n Report\n </a>\n</li>\n<li>\n<a class=\"\" href=\"/m/random/p/62/no-comment-in-attachment-reused-image/votes?type=up\">\n Activity\n </a>\n</li>\n<li class=\"dropdown__separator\"></li>\n<li>\n<a href=\"http://pasture-one-actor/object/xpwwBk2MP60\" rel=\"nofollow noopener noreferrer\" target=\"_blank\">\n Open original URL\n </a>\n</li>\n<li>\n<a data-action=\"clipboard#copy\" href=\"http://pasture-one-actor/object/xpwwBk2MP60\" rel=\"nofollow noopener noreferrer\">\n Copy original URL\n </a>\n</li>\n<li>\n<a data-action=\"clipboard#copy\" href=\"/m/random/p/62/no-comment-in-attachment-reused-image\">\n Copy Mbin URL\n </a>\n</li>\n</ul>\n</li>\n<li data-subject-target=\"loader\" style=\"display:none\">\n<div class=\"loader\" role=\"status\">\n<span class=\"visually-hidden\">Loading...</span>\n</div>\n</li>\n</menu>\n<div class=\"js-container\" data-subject-target=\"container\">\n</div>\n</footer>\n</blockquote>"
}