diff --git a/frontend/src/components/layout/LeftSidebar.tsx b/frontend/src/components/layout/LeftSidebar.tsx
index 9e0e627..5fbc79f 100644
--- a/frontend/src/components/layout/LeftSidebar.tsx
+++ b/frontend/src/components/layout/LeftSidebar.tsx
@@ -14,11 +14,12 @@ import {
 } from 'lucide-react'
 import clsx from 'clsx'
 import { AddSourceFolderDialog } from '../dialogs/AddSourceFolderDialog'
-import { sourceFolders, library } from '../../services/api'
+import { sourceFolders, library, photos as photosApi } from '../../services/api'
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
 import { toast } from '../ToastContainer'
 import { useFilterStore } from '../../store/filterStore'
 import { HeapsPanel } from '../heaps/HeapsPanel'
+import { PHOTO_DRAG_MIME } from '../timeline/PhotoThumbnail'
 
 interface TreeItem {
   id: string
@@ -41,6 +42,33 @@ export function LeftSidebar() {
   const setFlag = useFilterStore((s) => s.setFlag)
   const setFolderId = useFilterStore((s) => s.setFolderId)
   const filterFolderId = useFilterStore((s) => s.folderId)
+  const [dropTargetId, setDropTargetId] = useState<string | null>(null)
+
+  // Bulk discard mutation for the drag-onto-Discarded interaction.
+  const discardDropMutation = useMutation({
+    mutationFn: (photoIds: string[]) => photosApi.bulkDiscard(photoIds),
+    onSuccess: (_data, photoIds) => {
+      toast.success(
+        'Discarded',
+        `${photoIds.length} photo${photoIds.length > 1 ? 's' : ''}`
+      )
+      queryClient.invalidateQueries({ queryKey: ['photos'] })
+    },
+    onError: (e: any) =>
+      toast.error('Discard failed', e?.message || 'Unknown error'),
+  })
+
+  // Reads the dragged ids out of a drop event payload.
+  const readDragIds = (e: React.DragEvent): string[] | null => {
+    const raw = e.dataTransfer.getData(PHOTO_DRAG_MIME)
+    if (!raw) return null
+    try {
+      const parsed = JSON.parse(raw) as string[]
+      return Array.isArray(parsed) && parsed.length > 0 ? parsed : null
+    } catch {
+      return null
+    }
+  }
 
   // Map a library tree id to a filter-store mutation. Each "virtual node" in
   // the library tree is just a saved filter preset.
@@ -66,7 +94,6 @@ export function LeftSidebar() {
           clearAllFilters()
           setFolderId(folderId)
         }
-        // 'by-date' is still visual-only.
     }
   }
   
@@ -175,17 +202,31 @@ export function LeftSidebar() {
     return selectedItem === id
   }
 
+  // Which tree items accept photo drops, and what each does on drop.
+  const isDropTarget = (id: string): boolean => {
+    return id === 'discarded'
+  }
+
+  const handleDrop = (id: string, ids: string[]) => {
+    if (id === 'discarded') {
+      discardDropMutation.mutate(ids)
+    }
+  }
+
   const renderTreeItem = (item: TreeItem, depth: number = 0) => {
     const hasChildren = item.children && item.children.length > 0
     const isExpanded = expandedItems.has(item.id)
     const isSelected = isItemActive(item.id)
-    
+    const acceptsDrop = isDropTarget(item.id)
+    const isDropHover = dropTargetId === item.id
+
     return (
       <div key={item.id}>
         <div
           className={clsx(
             'group flex cursor-pointer items-center gap-1 rounded px-2 py-1 text-sm',
             isSelected ? 'bg-primary/20 text-primary' : 'text-text hover:bg-surface-2',
+            isDropHover && 'ring-2 ring-reject bg-reject/10',
             depth > 0 && 'text-[13px]'
           )}
           style={{ paddingLeft: `${8 + depth * 16}px` }}
@@ -197,6 +238,24 @@ export function LeftSidebar() {
               applyLibraryNode(item.id)
             }
           }}
+          onDragOver={acceptsDrop ? (e) => {
+            if (e.dataTransfer.types.includes(PHOTO_DRAG_MIME)) {
+              e.preventDefault()
+              e.dataTransfer.dropEffect = 'move'
+              if (dropTargetId !== item.id) setDropTargetId(item.id)
+            }
+          } : undefined}
+          onDragLeave={acceptsDrop ? (e) => {
+            if (!e.currentTarget.contains(e.relatedTarget as Node)) {
+              if (dropTargetId === item.id) setDropTargetId(null)
+            }
+          } : undefined}
+          onDrop={acceptsDrop ? (e) => {
+            e.preventDefault()
+            setDropTargetId(null)
+            const ids = readDragIds(e)
+            if (ids) handleDrop(item.id, ids)
+          } : undefined}
         >
           {/* Expand/Collapse Icon */}
           {hasChildren ? (
diff --git a/frontend/src/services/api.ts b/frontend/src/services/api.ts
index ad475df..3c1fbe0 100644
--- a/frontend/src/services/api.ts
+++ b/frontend/src/services/api.ts
@@ -69,15 +69,20 @@ export const photos = {
     return response.data
   },
 
-  bulkUpdate: async (photoIds: string[], data: {
-    rating?: number
-    flag?: string
-    heap_id?: string
-    discard?: boolean
-  }) => {
+  /** Bulk discard — matches the backend BulkAction schema. */
+  bulkDiscard: async (photoIds: string[]) => {
     const response = await api.post('/photos/bulk', {
-      photo_ids: photoIds,
-      ...data,
+      ids: photoIds,
+      action: 'discard',
+    })
+    return response.data
+  },
+
+  /** Bulk restore from discarded. */
+  bulkRestore: async (photoIds: string[]) => {
+    const response = await api.post('/photos/bulk', {
+      ids: photoIds,
+      action: 'restore',
     })
     return response.data
   },