diff --git a/extension/package.json b/extension/package.json
index 4e282561..46a16123 100644
--- a/extension/package.json
+++ b/extension/package.json
@@ -1,6 +1,6 @@
 {
   "name": "pigallery2-extension-kit",
-  "version": "2.0.2-edge",
+  "version": "2.0.3-edge",
   "description": "Interfaces for developing extensions for pigallery2",
   "author": "Patrik J. Braun",
   "homepage": "https://github.com/bpatrik/pigallery2",
diff --git a/package.json b/package.json
index b6c77533..40f81ba5 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "pigallery2",
-  "version": "2.0.2-edge",
+  "version": "2.0.3-edge",
   "description": "This is a photo gallery optimised for running low resource servers (especially on raspberry pi)",
   "author": "Patrik J. Braun",
   "homepage": "https://github.com/bpatrik/pigallery2",
diff --git a/src/backend/model/extension/ExtensionDecorator.ts b/src/backend/model/extension/ExtensionDecorator.ts
index a0870f49..81165960 100644
--- a/src/backend/model/extension/ExtensionDecorator.ts
+++ b/src/backend/model/extension/ExtensionDecorator.ts
@@ -10,11 +10,11 @@ export class ExtensionDecoratorObject {
 
 }
 
-export const ExtensionDecorator = <I extends [], O>(fn: (ee: IExtensionEvents) => IExtensionEvent<I, O>) => {
+export const ExtensionDecorator = <I extends unknown[], O>(fn: (ee: IExtensionEvents) => IExtensionEvent<I, O>) => {
   return (
     target: unknown,
     propertyName: string,
-    descriptor: PropertyDescriptor
+    descriptor: TypedPropertyDescriptor<(...args:I)=>Promise<O>>
   ) => {
 
     const targetMethod = descriptor.value;
diff --git a/src/backend/model/extension/ExtensionEvent.ts b/src/backend/model/extension/ExtensionEvent.ts
index 231b7b53..f9257205 100644
--- a/src/backend/model/extension/ExtensionEvent.ts
+++ b/src/backend/model/extension/ExtensionEvent.ts
@@ -1,6 +1,6 @@
 import {IExtensionAfterEventHandler, IExtensionBeforeEventHandler, IExtensionEvent} from './IExtension';
 
-export class ExtensionEvent<I, O> implements IExtensionEvent<I, O> {
+export class ExtensionEvent<I extends unknown[], O> implements IExtensionEvent<I, O> {
   protected beforeHandlers: IExtensionBeforeEventHandler<I, O>[] = [];
   protected afterHandlers: IExtensionAfterEventHandler<O>[] = [];
 
@@ -28,7 +28,7 @@ export class ExtensionEvent<I, O> implements IExtensionEvent<I, O> {
 
 
   public async triggerBefore(input: { inputs: I }, event: { stopPropagation: boolean }): Promise<{ inputs: I } | O> {
-    let pipe: { inputs: I } | O = input;
+    let pipe: { inputs: I} | O = input;
     if (this.beforeHandlers && this.beforeHandlers.length > 0) {
       const s = this.beforeHandlers.slice(0);
       for (let i = 0; i < s.length; ++i) {
diff --git a/src/backend/model/extension/IExtension.ts b/src/backend/model/extension/IExtension.ts
index cd59cf0e..aa5b6f53 100644
--- a/src/backend/model/extension/IExtension.ts
+++ b/src/backend/model/extension/IExtension.ts
@@ -9,13 +9,22 @@ import {ParamsDictionary} from 'express-serve-static-core';
 import {Connection} from 'typeorm';
 import {DynamicConfig} from '../../../common/entities/DynamicConfig';
 import {MediaDTOWithThPath} from '../messenger/Messenger';
+import {PhotoMetadata} from '../../../common/entities/PhotoDTO';
+import {VideoMetadata} from '../../../common/entities/VideoDTO';
+import {MediaRendererInput, SvgRendererInput} from '../fileaccess/PhotoWorker';
+import {SearchQueryDTO} from '../../../common/entities/SearchQueryDTO';
+import {CoverPhotoDTOWithID} from '../database/CoverManager';
+import {ParentDirectoryDTO} from '../../../common/entities/DirectoryDTO';
+import {DirectoryScanSettings} from '../fileaccess/DiskManager';
 
 
-export type IExtensionBeforeEventHandler<I, O> = (input: { inputs: I }, event: { stopPropagation: boolean }) => Promise<{ inputs: I } | O>;
+export type IExtensionBeforeEventHandler<I extends unknown[], O> = (input: { inputs: I }, event: { stopPropagation: boolean }) => Promise<{
+  inputs: I
+} | O>;
 export type IExtensionAfterEventHandler<O> = (output: O) => Promise<O>;
 
 
-export interface IExtensionEvent<I, O> {
+export interface IExtensionEvent<I extends unknown[], O> {
   before: (handler: IExtensionBeforeEventHandler<I, O>) => void;
   after: (handler: IExtensionAfterEventHandler<O>) => void;
 }
@@ -29,32 +38,40 @@ export interface IExtensionEvents {
      * Events for Directory and Album covers
      */
     CoverManager: {
-      getCoverForAlbum: IExtensionEvent<any, any>;
-      getCoverForDirectory: IExtensionEvent<any, any>
+      getCoverForAlbum: IExtensionEvent<[{
+        searchQuery: SearchQueryDTO;
+      }], CoverPhotoDTOWithID>;
+      getCoverForDirectory: IExtensionEvent<[{
+        id: number;
+        name: string;
+        path: string;
+      }], CoverPhotoDTOWithID>
       /**
        * Invalidates directory covers for a given directory and every parent
        */
-      invalidateDirectoryCovers: IExtensionEvent<any, any>;
+      invalidateDirectoryCovers: IExtensionEvent<[ParentDirectoryDTO], void>;
     },
     ImageRenderer: {
       /**
        * Renders a thumbnail or photo
        */
-      render: IExtensionEvent<any, any>
+      render: IExtensionEvent<[MediaRendererInput | SvgRendererInput], void>
     },
     /**
      * Reads exif, iptc, etc.. metadata for photos/videos
      */
     MetadataLoader: {
-      loadVideoMetadata: IExtensionEvent<any, any>,
-      loadPhotoMetadata: IExtensionEvent<any, any>
+      loadVideoMetadata: IExtensionEvent<[string], VideoMetadata>,
+      loadPhotoMetadata: IExtensionEvent<[string], PhotoMetadata>
     },
     /**
      * Scans the storage for a given directory and returns the list of child directories,
      * photos, videos and metafiles
      */
     DiskManager: {
-      scanDirectory: IExtensionEvent<any, any>
+      scanDirectory: IExtensionEvent<[
+        string,
+        DirectoryScanSettings], ParentDirectoryDTO>
     }
   };
 }