diff --git a/packages/dicomImageLoader/package.json b/packages/dicomImageLoader/package.json
index bc0e6ce8d4..3bd6d3b162 100644
--- a/packages/dicomImageLoader/package.json
+++ b/packages/dicomImageLoader/package.json
@@ -58,6 +58,7 @@
   "devDependencies": {
     "@babel/plugin-proposal-object-rest-spread": "^7.14.7",
     "@babel/runtime-corejs3": "^7.15.4",
+    "@types/emscripten": "^1.39.6",
     "@types/jasmine": "^4.3.1",
     "@types/karma": "^6.3.3",
     "chai": "^4.3.4",
diff --git a/packages/dicomImageLoader/src/shared/decoders/decodeJPEG2000.ts b/packages/dicomImageLoader/src/shared/decoders/decodeJPEG2000.ts
index 64fb8bbd2c..7423071cd1 100644
--- a/packages/dicomImageLoader/src/shared/decoders/decodeJPEG2000.ts
+++ b/packages/dicomImageLoader/src/shared/decoders/decodeJPEG2000.ts
@@ -1,4 +1,8 @@
 // https://emscripten.org/docs/api_reference/module.html
+import type {
+  J2KDecoder,
+  OpenJpegModule,
+} from '@cornerstonejs/codec-openjpeg/dist/openjpegwasm_decode';
 import openJpegFactory from '@cornerstonejs/codec-openjpeg/dist/openjpegwasm_decode';
 
 const openjpegWasm = new URL(
@@ -8,7 +12,11 @@ const openjpegWasm = new URL(
 
 import { ImageFrame, WebWorkerDecodeConfig } from '../../types';
 
-const local = {
+const local: {
+  codec: OpenJpegModule;
+  decoder: J2KDecoder;
+  decodeConfig: WebWorkerDecodeConfig;
+} = {
   codec: undefined,
   decoder: undefined,
   decodeConfig: {} as WebWorkerDecodeConfig,
@@ -26,7 +34,7 @@ export function initialize(
   const openJpegModule = openJpegFactory({
     locateFile: (f) => {
       if (f.endsWith('.wasm')) {
-        return openjpegWasm;
+        return openjpegWasm.toString();
       }
 
       return f;
diff --git a/packages/dicomImageLoader/src/shared/decoders/decodeJPEGBaseline8Bit.ts b/packages/dicomImageLoader/src/shared/decoders/decodeJPEGBaseline8Bit.ts
index 76715e7720..aff5618cba 100644
--- a/packages/dicomImageLoader/src/shared/decoders/decodeJPEGBaseline8Bit.ts
+++ b/packages/dicomImageLoader/src/shared/decoders/decodeJPEGBaseline8Bit.ts
@@ -1,6 +1,9 @@
-import { ByteArray } from 'dicom-parser';
-
+import type {
+  LibJpegTurbo8Bit,
+  OpenJpegModule,
+} from '@cornerstonejs/codec-libjpeg-turbo-8bit/dist/libjpegturbowasm_decode';
 import libjpegTurboFactory from '@cornerstonejs/codec-libjpeg-turbo-8bit/dist/libjpegturbowasm_decode';
+import { ByteArray } from 'dicom-parser';
 
 const libjpegTurboWasm = new URL(
   '@cornerstonejs/codec-libjpeg-turbo-8bit/dist/libjpegturbowasm_decode.wasm',
@@ -9,7 +12,10 @@ const libjpegTurboWasm = new URL(
 
 import { ImageFrame } from '../../types';
 
-const local = {
+const local: {
+  codec: OpenJpegModule;
+  decoder: LibJpegTurbo8Bit;
+} = {
   codec: undefined,
   decoder: undefined,
 };
@@ -22,7 +28,7 @@ function initLibjpegTurbo(): Promise<void> {
   const libjpegTurboModule = libjpegTurboFactory({
     locateFile: (f) => {
       if (f.endsWith('.wasm')) {
-        return libjpegTurboWasm;
+        return libjpegTurboWasm.toString();
       }
 
       return f;
diff --git a/packages/dicomImageLoader/src/shared/decoders/decodeJPEGLS.ts b/packages/dicomImageLoader/src/shared/decoders/decodeJPEGLS.ts
index 9db9712453..514b66ce0a 100644
--- a/packages/dicomImageLoader/src/shared/decoders/decodeJPEGLS.ts
+++ b/packages/dicomImageLoader/src/shared/decoders/decodeJPEGLS.ts
@@ -1,3 +1,7 @@
+import type {
+  CharlsModule,
+  JpegLSDecoder,
+} from '@cornerstonejs/codec-charls/dist/charlswasm_decode';
 import charlsFactory from '@cornerstonejs/codec-charls/dist/charlswasm_decode';
 
 const charlsWasm = new URL(
@@ -8,7 +12,11 @@ const charlsWasm = new URL(
 import { ByteArray } from 'dicom-parser';
 import { ImageFrame, WebWorkerDecodeConfig } from '../../types';
 
-const local = {
+const local: {
+  codec: CharlsModule;
+  decoder: JpegLSDecoder;
+  decodeConfig: WebWorkerDecodeConfig;
+} = {
   codec: undefined,
   decoder: undefined,
   decodeConfig: {} as WebWorkerDecodeConfig,
@@ -32,7 +40,7 @@ export function initialize(
   const charlsModule = charlsFactory({
     locateFile: (f) => {
       if (f.endsWith('.wasm')) {
-        return charlsWasm;
+        return charlsWasm.toString();
       }
 
       return f;
diff --git a/packages/dicomImageLoader/src/types/codec-charls.d.ts b/packages/dicomImageLoader/src/types/codec-charls.d.ts
new file mode 100644
index 0000000000..a565e418d7
--- /dev/null
+++ b/packages/dicomImageLoader/src/types/codec-charls.d.ts
@@ -0,0 +1,18 @@
+/// <reference types="emscripten" />
+
+declare module '@cornerstonejs/codec-charls/dist/charlswasm_decode' {
+  export class JpegLSDecoder {
+    decode: () => any;
+    getDecodedBuffer: () => any;
+    getEncodedBuffer: (length: number) => any;
+    getFrameInfo: () => any;
+    getInterleaveMode: () => any;
+    getNearLossless: () => any;
+  }
+  export interface CharlsModule extends EmscriptenModule {
+    JpegLSDecoder: typeof JpegLSDecoder;
+    getExceptionMessage: (exception: number) => any;
+  }
+  declare const Module: EmscriptenModuleFactory<CharlsModule>;
+  export default Module;
+}
diff --git a/packages/dicomImageLoader/src/types/codec-libjpeg-turbo-8bit.d.ts b/packages/dicomImageLoader/src/types/codec-libjpeg-turbo-8bit.d.ts
new file mode 100644
index 0000000000..2ceebc888e
--- /dev/null
+++ b/packages/dicomImageLoader/src/types/codec-libjpeg-turbo-8bit.d.ts
@@ -0,0 +1,15 @@
+/// <reference types="emscripten" />
+
+declare module '@cornerstonejs/codec-libjpeg-turbo-8bit/dist/libjpegturbowasm_decode' {
+  export class LibJpegTurbo8Bit {
+    decode: () => any;
+    getDecodedBuffer: () => any;
+    getEncodedBuffer: (length: number) => any;
+    getFrameInfo: () => any;
+  }
+  export interface OpenJpegModule extends EmscriptenModule {
+    JPEGDecoder: typeof LibJpegTurbo8Bit;
+  }
+  declare const Module: EmscriptenModuleFactory<OpenJpegModule>;
+  export default Module;
+}
diff --git a/packages/dicomImageLoader/src/types/codec-openjpeg.d.ts b/packages/dicomImageLoader/src/types/codec-openjpeg.d.ts
new file mode 100644
index 0000000000..10467e472f
--- /dev/null
+++ b/packages/dicomImageLoader/src/types/codec-openjpeg.d.ts
@@ -0,0 +1,24 @@
+/// <reference types="emscripten" />
+
+declare module '@cornerstonejs/codec-openjpeg/dist/openjpegwasm_decode' {
+  export class J2KDecoder {
+    decode: () => any;
+    getBlockDimensions: () => any;
+    getColorSpace: () => any;
+    getDecodedBuffer: () => any;
+    getEncodedBuffer: (length: number) => any;
+    getFrameInfo: () => any;
+    getImageOffset: () => any;
+    getIsReversible: () => any;
+    getNumDecompositions: () => any;
+    getNumLayers: () => any;
+    getProgressionOrder: () => number;
+    getTileOffset: () => any;
+    getTileSize: () => any;
+  }
+  export interface OpenJpegModule extends EmscriptenModule {
+    J2KDecoder: typeof J2KDecoder;
+  }
+  declare const Module: EmscriptenModuleFactory<OpenJpegModule>;
+  export default Module;
+}
diff --git a/yarn.lock b/yarn.lock
index 66b09117f5..392311a790 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5520,6 +5520,11 @@
     "@types/got" "^8"
     "@types/node" "*"
 
+"@types/emscripten@^1.39.6":
+  version "1.39.6"
+  resolved "https://registry.yarnpkg.com/@types/emscripten/-/emscripten-1.39.6.tgz#698b90fe60d44acf93c31064218fbea93fbfd85a"
+  integrity sha512-H90aoynNhhkQP6DRweEjJp5vfUVdIj7tdPLsu7pq89vODD/lcugKfZOsfgwpvM6XUewEp2N5dCg1Uf3Qe55Dcg==
+
 "@types/eslint-scope@^3.7.0", "@types/eslint-scope@^3.7.3":
   version "3.7.3"
   resolved "https://registry.yarnpkg.com/@types/eslint-scope/-/eslint-scope-3.7.3.tgz#125b88504b61e3c8bc6f870882003253005c3224"