fix display size on repo page

pkg/appview/handlers/repository.go

@@ -24,7 +24,7 @@ import (
 type SelectedTagData struct {
 	Info            *db.TagWithPlatforms
 	LayerCount      int
-	CompressedSize  int64 // total across all platforms
+	CompressedSize  int64 // largest platform's size for multi-arch; size for single-arch
 	ScanBatchParams []template.HTML
 }
 
@@ -122,14 +122,18 @@ func (h *RepositoryPageHandler) ServeHTTP(w http.ResponseWriter, r *http.Request
 			}
 			tagData.Platforms = platforms
 
-			// Compute total compressed size across all platforms
-			var totalSize int64
+			// For multi-arch, show the largest platform's size — a client only
+			// pulls one platform, so summing across all would overstate the
+			// download size.
+			var displaySize int64
 			if tagData.IsMultiArch {
 				for _, p := range platforms {
-					totalSize += p.CompressedSize
+					if p.CompressedSize > displaySize {
+						displaySize = p.CompressedSize
+					}
 				}
 			} else {
-				totalSize = tagData.CompressedSize
+				displaySize = tagData.CompressedSize
 			}
 
 			// Get layer count from image config (includes empty layers)
@@ -162,7 +166,7 @@ func (h *RepositoryPageHandler) ServeHTTP(w http.ResponseWriter, r *http.Request
 			selectedTag = &SelectedTagData{
 				Info:            tagData,
 				LayerCount:      layerCount,
-				CompressedSize:  totalSize,
+				CompressedSize:  displaySize,
 				ScanBatchParams: scanBatchParams,
 			}
 		}