diff --git a/lib/imageRouter/azure.ts b/lib/imageRouter/azure.ts
index bc601659..1a2df524 100644
--- a/lib/imageRouter/azure.ts
+++ b/lib/imageRouter/azure.ts
@@ -6,7 +6,7 @@ import azure from "azure-storage";
 import config from "../config";
 import {logger} from "../logger";
 
-export function uploadImage(imagePath, callback) {
+export function uploadImage(imagePath: string, callback?: (err: Error | null, url ?: string) => void): void {
   if (!imagePath || typeof imagePath !== 'string') {
     callback(new Error('Image path is missing or wrong'), null)
     return
@@ -19,11 +19,11 @@ export function uploadImage(imagePath, callback) {
 
   const azureBlobService = azure.createBlobService(config.azure.connectionString)
 
-  azureBlobService.createContainerIfNotExists(config.azure.container, {publicAccessLevel: 'blob'}, function (err, result, response) {
+  azureBlobService.createContainerIfNotExists(config.azure.container, {publicAccessLevel: 'blob'}, function (err) {
     if (err) {
       callback(new Error(err.message), null)
     } else {
-      azureBlobService.createBlockBlobFromLocalFile(config.azure.container, path.basename(imagePath), imagePath, function (err, result, response) {
+      azureBlobService.createBlockBlobFromLocalFile(config.azure.container, path.basename(imagePath), imagePath, function (err, result) {
         if (err) {
           callback(new Error(err.message), null)
         } else {
diff --git a/lib/imageRouter/filesystem.ts b/lib/imageRouter/filesystem.ts
index c1a08183..5b5fffb7 100644
--- a/lib/imageRouter/filesystem.ts
+++ b/lib/imageRouter/filesystem.ts
@@ -34,7 +34,7 @@ function pickFilename(defaultFilename) {
   throw new Error('file exists.')
 }
 
-export function uploadImage(imagePath, callback) {
+export function uploadImage(imagePath: string, callback: (err: Error | null, url?: string) => void): void {
   if (!imagePath || typeof imagePath !== 'string') {
     callback(new Error('Image path is missing or wrong'), null)
     return
diff --git a/lib/imageRouter/imgur.ts b/lib/imageRouter/imgur.ts
index 58902bcf..dd85729f 100644
--- a/lib/imageRouter/imgur.ts
+++ b/lib/imageRouter/imgur.ts
@@ -4,7 +4,7 @@ import imgur from "@hackmd/imgur";
 import config from "../config";
 import {logger} from "../logger";
 
-export function uploadImage(imagePath, callback) {
+export function uploadImage(imagePath: string, callback: (err: Error | null, url?: string) => void): void {
   if (!imagePath || typeof imagePath !== 'string') {
     callback(new Error('Image path is missing or wrong'), null)
     return
diff --git a/lib/imageRouter/lutim.ts b/lib/imageRouter/lutim.ts
index 67fa6214..4d4a385c 100644
--- a/lib/imageRouter/lutim.ts
+++ b/lib/imageRouter/lutim.ts
@@ -4,7 +4,7 @@ import config from "../config";
 import {logger} from "../logger";
 
 
-export function uploadImage(imagePath, callback) {
+export function uploadImage(imagePath: string, callback: (err: Error | null, url: string) => void): void {
   if (!imagePath || typeof imagePath !== 'string') {
     callback(new Error('Image path is missing or wrong'), null)
     return
diff --git a/lib/imageRouter/minio.ts b/lib/imageRouter/minio.ts
index f8c36ba8..f21e4f78 100644
--- a/lib/imageRouter/minio.ts
+++ b/lib/imageRouter/minio.ts
@@ -15,7 +15,7 @@ const minioClient = new Minio.Client({
   secretKey: config.minio.secretKey
 })
 
-export function uploadImage(imagePath, callback) {
+export function uploadImage(imagePath: string, callback: (err: Error | null, url?: string) => void): void {
   if (!imagePath || typeof imagePath !== 'string') {
     callback(new Error('Image path is missing or wrong'), null)
     return
@@ -37,7 +37,7 @@ export function uploadImage(imagePath, callback) {
 
     minioClient.putObject(config.s3bucket, key, buffer, buffer.length, {
       ContentType: getImageMimeType(imagePath)
-    }, function (err, data) {
+    }, function (err) {
       if (err) {
         callback(err, null)
         return
diff --git a/lib/imageRouter/s3.ts b/lib/imageRouter/s3.ts
index 03ceea79..9de419a2 100644
--- a/lib/imageRouter/s3.ts
+++ b/lib/imageRouter/s3.ts
@@ -20,7 +20,7 @@ const s3 = new S3Client({
   endpoint: config.s3.endpoint
 })
 
-export function uploadImage(imagePath, callback) {
+export function uploadImage(imagePath: string, callback: (err: Error | null, url: string) => void): void {
   if (!imagePath || typeof imagePath !== 'string') {
     callback(new Error('Image path is missing or wrong'), null)
     return
@@ -44,12 +44,12 @@ export function uploadImage(imagePath, callback) {
     }
     const mimeType = getImageMimeType(imagePath)
     if (mimeType) {
-      params.ContentType = mimeType
+      params.ContentType = mimeType as string
     }
 
     const command = new PutObjectCommand(params)
 
-    s3.send(command).then(data => {
+    s3.send(command).then(() => {
       let s3Endpoint = 's3.amazonaws.com'
       if (config.s3.endpoint) {
         s3Endpoint = config.s3.endpoint