diff --git a/app/javascript/mastodon/components/media_gallery.jsx b/app/javascript/mastodon/components/media_gallery.jsx
index 91459a1285c..b7132482ac1 100644
--- a/app/javascript/mastodon/components/media_gallery.jsx
+++ b/app/javascript/mastodon/components/media_gallery.jsx
@@ -21,6 +21,14 @@ const messages = defineMessages({
   toggle_visible: { id: 'media_gallery.toggle_visible', defaultMessage: '{number, plural, one {Hide image} other {Hide images}}' },
 });
 
+const colCount = function(size) {
+  return Math.max(Math.floor(Math.sqrt(size)), 2);
+};
+
+const rowCount = function(size) {
+  return Math.ceil(size / colCount(size));
+};
+
 class Item extends PureComponent {
 
   static propTypes = {
@@ -92,14 +100,18 @@ class Item extends PureComponent {
     let badges = [], thumbnail;
 
     let width  = 50;
-    let height = 100;
+    let height = 50;
 
-    if (size === 1) {
+    const cols = colCount(size);
+    const remaining = (-size % cols + cols) % cols;
+    const largeCount = Math.floor(remaining / 3); // width=2, height=2
+    const mediumCount = remaining % 3; // height=2
+
+    if (size === 1 || index < largeCount) {
       width = 100;
-    }
-
-    if (size === 4 || (size === 3 && index > 0)) {
-      height = 50;
+      height = 100;
+    } else if (size === 2 || index < largeCount + mediumCount) {
+      height = 100;
     }
 
     if (attachment.get('description')?.length > 0) {
@@ -302,16 +314,21 @@ class MediaGallery extends PureComponent {
     if (this.isFullSizeEligible()) {
       style.aspectRatio = `${this.props.media.getIn([0, 'meta', 'small', 'aspect'])}`;
     } else {
+      const cols = colCount(media.size);
+      const rows = rowCount(media.size);
+      style.gridTemplateColumns = `repeat(${cols}, 1fr)`;
+      style.gridTemplateRows = `repeat(${rows}, 1fr)`;
+
       style.aspectRatio = '3 / 2';
     }
 
-    const size     = media.take(4).size;
+    const size     = media.size;
     const uncached = media.every(attachment => attachment.get('type') === 'unknown');
 
     if (this.isFullSizeEligible()) {
       children = <Item standalone autoplay={autoplay} onClick={this.handleClick} attachment={media.get(0)} lang={lang} displayWidth={width} visible={visible} />;
     } else {
-      children = media.take(4).map((attachment, i) => <Item key={attachment.get('id')} autoplay={autoplay} onClick={this.handleClick} attachment={attachment} index={i} lang={lang} size={size} displayWidth={width} visible={visible || uncached} />);
+      children = media.map((attachment, i) => <Item key={attachment.get('id')} autoplay={autoplay} onClick={this.handleClick} attachment={attachment} index={i} lang={lang} size={size} displayWidth={width} visible={visible || uncached} />);
     }
 
     if (uncached) {
diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 85195f4c395..86c9f5c6205 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -110,7 +110,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
   def process_status_params
     @status_parser = ActivityPub::Parser::StatusParser.new(@json, followers_collection: @account.followers_url, object: @object)
 
-    attachment_ids = process_attachments.take(4).map(&:id)
+    attachment_ids = process_attachments.take(16).map(&:id)
 
     @params = {
       uri: @status_parser.uri,
@@ -260,7 +260,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     as_array(@object['attachment']).each do |attachment|
       media_attachment_parser = ActivityPub::Parser::MediaAttachmentParser.new(attachment)
 
-      next if media_attachment_parser.remote_url.blank? || media_attachments.size >= 4
+      next if media_attachment_parser.remote_url.blank? || media_attachments.size >= 16
 
       begin
         media_attachment = MediaAttachment.create(
diff --git a/app/services/activitypub/process_status_update_service.rb b/app/services/activitypub/process_status_update_service.rb
index fb2b33114ed..002c270cc05 100644
--- a/app/services/activitypub/process_status_update_service.rb
+++ b/app/services/activitypub/process_status_update_service.rb
@@ -73,7 +73,7 @@ class ActivityPub::ProcessStatusUpdateService < BaseService
     as_array(@json['attachment']).each do |attachment|
       media_attachment_parser = ActivityPub::Parser::MediaAttachmentParser.new(attachment)
 
-      next if media_attachment_parser.remote_url.blank? || @next_media_attachments.size > 4
+      next if media_attachment_parser.remote_url.blank? || @next_media_attachments.size > 16
 
       begin
         media_attachment   = previous_media_attachments.find { |previous_media_attachment| previous_media_attachment.remote_url == media_attachment_parser.remote_url }