diff --git a/.eslintrc b/.eslintrc
index c5efba2..9b0a890 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -22,5 +22,6 @@
         "@typescript-eslint/no-unused-vars": "off",
         "@typescript-eslint/class-name-casing": "off",
         "prettier/prettier": "error"
-    }
+    },
+    "root": true
 }
diff --git a/src/core/__mocks__/context.ts b/src/core/__mocks__/context.ts
index 3a03a8d..b5fe7dc 100644
--- a/src/core/__mocks__/context.ts
+++ b/src/core/__mocks__/context.ts
@@ -9,10 +9,9 @@ export class Context {
 
     constructor() {
         this.cache = {
-            addImage: jest.fn().mockImplementation((src: string): Promise<void> => {
-                const result = Promise.resolve();
-                this._cache[src] = result;
-                return result;
+            addImage: jest.fn().mockImplementation((src: string): boolean => {
+                this._cache[src] = Promise.resolve();
+                return true;
             })
         };
     }
diff --git a/src/core/__tests__/cache-storage.ts b/src/core/__tests__/cache-storage.ts
index 7844fa0..1fa5d85 100644
--- a/src/core/__tests__/cache-storage.ts
+++ b/src/core/__tests__/cache-storage.ts
@@ -125,88 +125,88 @@ describe('cache-storage', () => {
         xhr.splice(0, xhr.length);
         images.splice(0, images.length);
     });
-    it('addImage adds images to cache', async () => {
+    it('addImage adds images to cache', () => {
         const {cache} = createMockContext('http://example.com', {proxy: null});
-        await cache.addImage('http://example.com/test.jpg');
-        await cache.addImage('http://example.com/test2.jpg');
+        cache.addImage('http://example.com/test.jpg');
+        cache.addImage('http://example.com/test2.jpg');
 
         deepStrictEqual(images.length, 2);
         deepStrictEqual(images[0].src, 'http://example.com/test.jpg');
         deepStrictEqual(images[1].src, 'http://example.com/test2.jpg');
     });
 
-    it('addImage should not add duplicate entries', async () => {
+    it('addImage should not add duplicate entries', () => {
         const {cache} = createMockContext('http://example.com');
-        await cache.addImage('http://example.com/test.jpg');
-        await cache.addImage('http://example.com/test.jpg');
+        cache.addImage('http://example.com/test.jpg');
+        cache.addImage('http://example.com/test.jpg');
 
         deepStrictEqual(images.length, 1);
         deepStrictEqual(images[0].src, 'http://example.com/test.jpg');
     });
 
     describe('svg', () => {
-        it('should add svg images correctly', async () => {
+        it('should add svg images correctly', () => {
             const {cache} = createMockContext('http://example.com');
-            await cache.addImage('http://example.com/test.svg');
-            await cache.addImage('http://example.com/test2.svg');
+            cache.addImage('http://example.com/test.svg');
+            cache.addImage('http://example.com/test2.svg');
 
             deepStrictEqual(images.length, 2);
             deepStrictEqual(images[0].src, 'http://example.com/test.svg');
             deepStrictEqual(images[1].src, 'http://example.com/test2.svg');
         });
 
-        it('should omit svg images if not supported', async () => {
+        it('should omit svg images if not supported', () => {
             setFeatures({SUPPORT_SVG_DRAWING: false});
             const {cache} = createMockContext('http://example.com');
-            await cache.addImage('http://example.com/test.svg');
-            await cache.addImage('http://example.com/test2.svg');
+            cache.addImage('http://example.com/test.svg');
+            cache.addImage('http://example.com/test2.svg');
 
             deepStrictEqual(images.length, 0);
         });
     });
 
     describe('cross-origin', () => {
-        it('addImage should not add images it cannot load/render', async () => {
+        it('addImage should not add images it cannot load/render', () => {
             const {cache} = createMockContext('http://example.com', {
                 proxy: undefined
             });
-            await cache.addImage('http://html2canvas.hertzen.com/test.jpg');
+            cache.addImage('http://html2canvas.hertzen.com/test.jpg');
             deepStrictEqual(images.length, 0);
         });
 
-        it('addImage should add images if tainting enabled', async () => {
+        it('addImage should add images if tainting enabled', () => {
             const {cache} = createMockContext('http://example.com', {
                 allowTaint: true,
                 proxy: undefined
             });
-            await cache.addImage('http://html2canvas.hertzen.com/test.jpg');
+            cache.addImage('http://html2canvas.hertzen.com/test.jpg');
             deepStrictEqual(images.length, 1);
             deepStrictEqual(images[0].src, 'http://html2canvas.hertzen.com/test.jpg');
             deepStrictEqual(images[0].crossOrigin, undefined);
         });
 
-        it('addImage should add images if cors enabled', async () => {
+        it('addImage should add images if cors enabled', () => {
             const {cache} = createMockContext('http://example.com', {useCORS: true});
-            await cache.addImage('http://html2canvas.hertzen.com/test.jpg');
+            cache.addImage('http://html2canvas.hertzen.com/test.jpg');
             deepStrictEqual(images.length, 1);
             deepStrictEqual(images[0].src, 'http://html2canvas.hertzen.com/test.jpg');
             deepStrictEqual(images[0].crossOrigin, 'anonymous');
         });
 
-        it('addImage should not add images if cors enabled but not supported', async () => {
+        it('addImage should not add images if cors enabled but not supported', () => {
             setFeatures({SUPPORT_CORS_IMAGES: false});
 
             const {cache} = createMockContext('http://example.com', {
                 useCORS: true,
                 proxy: undefined
             });
-            await cache.addImage('http://html2canvas.hertzen.com/test.jpg');
+            cache.addImage('http://html2canvas.hertzen.com/test.jpg');
             deepStrictEqual(images.length, 0);
         });
 
-        it('addImage should not add images to proxy if cors enabled', async () => {
+        it('addImage should not add images to proxy if cors enabled', () => {
             const {cache} = createMockContext('http://example.com', {useCORS: true});
-            await cache.addImage('http://html2canvas.hertzen.com/test.jpg');
+            cache.addImage('http://html2canvas.hertzen.com/test.jpg');
             deepStrictEqual(images.length, 1);
             deepStrictEqual(images[0].src, 'http://html2canvas.hertzen.com/test.jpg');
             deepStrictEqual(images[0].crossOrigin, 'anonymous');
@@ -214,7 +214,7 @@ describe('cache-storage', () => {
 
         it('addImage should use proxy ', async () => {
             const {cache} = createMockContext('http://example.com');
-            await cache.addImage('http://html2canvas.hertzen.com/test.jpg');
+            cache.addImage('http://html2canvas.hertzen.com/test.jpg');
             deepStrictEqual(xhr.length, 1);
             deepStrictEqual(
                 xhr[0].url,
@@ -230,7 +230,7 @@ describe('cache-storage', () => {
             const {cache} = createMockContext('http://example.com', {
                 imageTimeout: 10
             });
-            await cache.addImage('http://html2canvas.hertzen.com/test.jpg');
+            cache.addImage('http://html2canvas.hertzen.com/test.jpg');
 
             deepStrictEqual(xhr.length, 1);
             deepStrictEqual(
@@ -250,7 +250,7 @@ describe('cache-storage', () => {
 
     it('match should return cache entry', async () => {
         const {cache} = createMockContext('http://example.com');
-        await cache.addImage('http://example.com/test.jpg');
+        cache.addImage('http://example.com/test.jpg');
 
         if (images[0].onload) {
             images[0].onload();
diff --git a/src/core/cache-storage.ts b/src/core/cache-storage.ts
index d935330..13cc5c2 100644
--- a/src/core/cache-storage.ts
+++ b/src/core/cache-storage.ts
@@ -39,20 +39,15 @@ export class Cache {
 
     constructor(private readonly context: Context, private readonly _options: ResourceOptions) {}
 
-    addImage(src: string): Promise<void> {
-        const result = Promise.resolve();
-        if (this.has(src)) {
-            return result;
-        }
-
+    addImage(src: string): boolean {
+        if (this.has(src)) return true;
         if (isBlobImage(src) || isRenderable(src)) {
             (this._cache[src] = this.loadImage(src)).catch(() => {
                 // prevent unhandled rejection
             });
-            return result;
+            return true;
         }
-
-        return result;
+        return false;
     }
 
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
diff --git a/src/core/features.ts b/src/core/features.ts
index 52a8c51..78286ce 100644
--- a/src/core/features.ts
+++ b/src/core/features.ts
@@ -157,7 +157,7 @@ export const createForeignObjectSVG = (
     return svg;
 };
 
-export const serializeSvg = (svg: SVGSVGElement | SVGForeignObjectElement, encoding: string = ''): string => {
+export const serializeSvg = (svg: SVGSVGElement | SVGForeignObjectElement, encoding = ''): string => {
     const svgPrefix = 'data:image/svg+xml';
     const selializedSvg = new XMLSerializer().serializeToString(svg);
     const encodedSvg = encoding === 'base64' ? btoa(selializedSvg) : encodeURIComponent(selializedSvg);
@@ -171,6 +171,7 @@ export const deserializeSvg = (svg: string): SVGSVGElement | SVGForeignObjectEle
     const document = domParser.parseFromString(encodedSvg, 'image/svg+xml');
     const parserError = document.querySelector('parsererror');
     if (parserError) {
+        // eslint-disable-next-line @typescript-eslint/ban-ts-comment
         // @ts-ignore: Expected 0-1 arguments, but got 2.
         throw new Error('Deserialisation failed', {cause: parserError});
     }