diff --git a/strange_eons_to_arkhamdb.js b/strange_eons_to_arkhamdb.js
index 33a2774..f262996 100644
--- a/strange_eons_to_arkhamdb.js
+++ b/strange_eons_to_arkhamdb.js
@@ -260,9 +260,13 @@ for (let member in recurseAllChildren(Eons.getOpenProject())) {
         let card_data = build_card(component);
         cards.push(card_data);
 
-        const export_dir = new File(member.parent.file, 'export');
-        export_dir.mkdir();
-        exportCard(component, new File(export_dir, card_data.code + '.png'));
+        let export_dir = new File(member.parent.file, 'export');
+        let target_file = new File(export_dir, card_data.code + '.png');
+        if (!target_file.exists() || member.file.lastModified() > target_file.lastModified()) {
+          printf("Image for '%s' is out of date, rebuilding...\n", member);
+          export_dir.mkdir();
+          exportCard(component, target_file);
+        }
       }
     }
   } catch (ex) {