diff --git a/com.woltlab.wcf/templates/attachments.tpl b/com.woltlab.wcf/templates/attachments.tpl
index 5034f73fe37..9c76cb29d7c 100644
--- a/com.woltlab.wcf/templates/attachments.tpl
+++ b/com.woltlab.wcf/templates/attachments.tpl
@@ -1,14 +1,17 @@
-{if $attachmentList && $attachmentList->getGroupedObjects($objectID)|count}
+{if !$attachments|isset && $attachmentList && $attachmentList->getGroupedObjects($objectID)|count}
+	{assign var='attachments' value=$attachmentList->getGroupedObjects($objectID)}
+{/if}
+{if !$attachments|empty}
 	{hascontent}
 		<section class="section attachmentThumbnailList">
 			<h2 class="messageSectionTitle">{lang}wcf.attachment.images{/lang}</h2>
 			
 			<ul class="inlineList">
 				{content}
-					{foreach from=$attachmentList->getGroupedObjects($objectID) item=attachment}
+					{foreach from=$attachments item=attachment}
 						{if $attachment->showAsImage() && !$attachment->isEmbedded()}
 							<li class="attachmentThumbnail" data-attachment-id="{$attachment->attachmentID}">
-								<a href="{$attachment->getLink()}"{if $attachment->canDownload()} data-type="image" data-fancybox="message-{$attachmentList->getObjectTypeName()}-{$objectID}" data-caption="{$attachment->filename}" aria-label="{lang}wcf.attachment.image.title{/lang}"{/if}>
+								<a href="{$attachment->getLink()}"{if $attachment->canDownload()} data-type="image" data-fancybox="{$attachment->getFancyboxTag()}" data-caption="{$attachment->filename}" aria-label="{lang}wcf.attachment.image.title{/lang}"{/if}>
 									<div class="attachmentThumbnailContainer">
 										<span class="attachmentThumbnailImage">
 											{if $attachment->hasThumbnail()}
@@ -66,7 +69,7 @@
 
 			<div class="messageAttachmentList">
 				{content}
-					{foreach from=$attachmentList->getGroupedObjects($objectID) item=attachment}
+					{foreach from=$attachments item=attachment}
 						{if $attachment->showAsFile() && !$attachment->isEmbedded()}
 							<a href="{$attachment->getLink()}" class="messageAttachment jsTooltip" title="{lang}wcf.attachment.file.title{/lang}">
 								<span class="messageAttachmentIcon">
diff --git a/com.woltlab.wcf/templates/entryAttachments.tpl b/com.woltlab.wcf/templates/entryAttachments.tpl
index 06f1596133b..ecc4e51c191 100644
--- a/com.woltlab.wcf/templates/entryAttachments.tpl
+++ b/com.woltlab.wcf/templates/entryAttachments.tpl
@@ -1,14 +1,17 @@
-{if $attachmentList && $attachmentList->getGroupedObjects($objectID)|count}
+{if !$attachments|isset && $attachmentList && $attachmentList->getGroupedObjects($objectID)|count}
+	{assign var='attachments' value=$attachmentList->getGroupedObjects($objectID)}
+{/if}
+{if !$attachments|empty}
 	{hascontent}
 		<section class="entry__attachments__thumbnails">
 			<h2 class="entry__attachments__title">{lang}wcf.attachment.images{/lang}</h2>
 			
 			<ul class="inlineList">
 				{content}
-					{foreach from=$attachmentList->getGroupedObjects($objectID) item=attachment}
+					{foreach from=$attachments item=attachment}
 						{if $attachment->showAsImage() && !$attachment->isEmbedded()}
 							<li class="attachmentThumbnail" data-attachment-id="{$attachment->attachmentID}">
-								<a href="{$attachment->getLink()}"{if $attachment->canDownload()} data-type="image" data-fancybox="message-{$attachmentList->getObjectTypeName()}-{$objectID}" data-caption="{$attachment->filename}" aria-label="{lang}wcf.attachment.image.title{/lang}"{/if}>
+								<a href="{$attachment->getLink()}"{if $attachment->canDownload()} data-type="image" data-fancybox="{$attachment->getFancyboxTag()}" data-caption="{$attachment->filename}" aria-label="{lang}wcf.attachment.image.title{/lang}"{/if}>
 									<div class="attachmentThumbnailContainer">
 										<span class="attachmentThumbnailImage">
 											{if $attachment->hasThumbnail()}
@@ -66,7 +69,7 @@
 
 			<div class="messageAttachmentList">
 				{content}
-					{foreach from=$attachmentList->getGroupedObjects($objectID) item=attachment}
+					{foreach from=$attachments item=attachment}
 						{if $attachment->showAsFile() && !$attachment->isEmbedded()}
 							<a href="{$attachment->getLink()}" class="messageAttachment jsTooltip" title="{lang}wcf.attachment.file.title{/lang}">
 								<span class="messageAttachmentIcon">
diff --git a/wcfsetup/install/files/lib/data/attachment/Attachment.class.php b/wcfsetup/install/files/lib/data/attachment/Attachment.class.php
index bc52ceb478a..f127f39e323 100644
--- a/wcfsetup/install/files/lib/data/attachment/Attachment.class.php
+++ b/wcfsetup/install/files/lib/data/attachment/Attachment.class.php
@@ -538,4 +538,16 @@ public function getImageData(?int $minWidth = null, ?int $minHeight = null): ?Im
 
         return new ImageData($this->getLink(), $this->width, $this->height);
     }
+
+    /**
+     * @return string
+     */
+    public function getFancyboxTag(): string
+    {
+        return \sprintf(
+            'attachments-%s-%s',
+            ObjectTypeCache::getInstance()->getObjectType($this->objectTypeID)->objectType,
+            $this->objectID
+        );
+    }
 }
diff --git a/wcfsetup/install/files/lib/data/attachment/GroupedAttachmentList.class.php b/wcfsetup/install/files/lib/data/attachment/GroupedAttachmentList.class.php
index 0b6add691d5..77d2b19c725 100644
--- a/wcfsetup/install/files/lib/data/attachment/GroupedAttachmentList.class.php
+++ b/wcfsetup/install/files/lib/data/attachment/GroupedAttachmentList.class.php
@@ -8,23 +8,18 @@
 /**
  * Represents a grouped list of attachments.
  *
- * @author  Marcel Werk
- * @copyright   2001-2019 WoltLab GmbH
- * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @author      Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  */
 class GroupedAttachmentList extends AttachmentList
 {
     /**
-     * grouped objects
      * @var array<int, array<int, Attachment>>
      */
-    public $groupedObjects = [];
+    public array $groupedObjects = [];
 
-    /**
-     * object type
-     * @var ObjectType
-     */
-    protected $objectType;
+    protected ObjectType $objectType;
 
     /**
      * @inheritDoc
@@ -36,19 +31,19 @@ class GroupedAttachmentList extends AttachmentList
      */
     public $sqlOrderBy = 'attachment.showOrder';
 
-    /**
-     * Creates a new GroupedAttachmentList object.
-     *
-     * @param string $objectType
-     */
-    public function __construct($objectType)
+    public function __construct(string $objectType)
     {
         parent::__construct();
 
-        $this->objectType = ObjectTypeCache::getInstance()->getObjectTypeByName(
+        $objectTypeObj = ObjectTypeCache::getInstance()->getObjectTypeByName(
             'com.woltlab.wcf.attachment.objectType',
             $objectType
         );
+        if ($objectType === null) {
+            throw new \BadMethodCallException("unknown attachment object type '{$objectType}'");
+        }
+
+        $this->objectType = $objectTypeObj;
         $this->getConditionBuilder()->add('attachment.objectTypeID = ?', [$this->objectType->objectTypeID]);
 
         $this->getConditionBuilder()->add(
@@ -70,10 +65,8 @@ public function __construct($objectType)
         );
     }
 
-    /**
-     * @inheritDoc
-     */
-    public function readObjects()
+    #[\Override]
+    public function readObjects(): void
     {
         parent::readObjects();
 
@@ -91,9 +84,8 @@ public function readObjects()
      * Sets the permissions for attachment access.
      *
      * @param array<string, bool> $permissions
-     * @return void
      */
-    public function setPermissions(array $permissions)
+    public function setPermissions(array $permissions): void
     {
         foreach ($this->objects as $attachment) {
             $attachment->setPermissions($permissions);
@@ -101,12 +93,11 @@ public function setPermissions(array $permissions)
     }
 
     /**
-     * Returns the objects of the list.
+     * Returns the attachments associated with the given objectID.
      *
-     * @param int $objectID
-     * @return  Attachment[]
+     * @return Attachment[]
      */
-    public function getGroupedObjects($objectID)
+    public function getGroupedObjects(int $objectID): array
     {
         if (isset($this->groupedObjects[$objectID])) {
             return $this->groupedObjects[$objectID];