diff --git a/src/app/shared/services/image-store/image-store.service.ts b/src/app/shared/services/image-store/image-store.service.ts
index da4f0273e..8bbbf6f7f 100644
--- a/src/app/shared/services/image-store/image-store.service.ts
+++ b/src/app/shared/services/image-store/image-store.service.ts
@@ -66,8 +66,24 @@ export class ImageStore {
     return result.data;
   }
 
-  async write(base64: string, mimeType: MimeType) {
+  async write(
+    base64: string,
+    mimeType: MimeType,
+    onWriteExistStrategy = OnWriteExistStrategy.REPLACE
+  ) {
     const index = await sha256WithBase64(base64);
+    await this.initialize();
+    if (onWriteExistStrategy === OnWriteExistStrategy.REPLACE) {
+      return this._write(index, base64, mimeType);
+    }
+    const exists = await this.exists(index);
+    if (exists) {
+      return index;
+    }
+    return this._write(index, base64, mimeType);
+  }
+
+  private async _write(index: string, base64: string, mimeType: MimeType) {
     await this.initialize();
     return this.mutex.runExclusive(async () => {
       const imageExtension = await this.setImageExtension(index, mimeType);
@@ -226,3 +242,8 @@ interface Thumbnail extends Tuple {
   readonly imageIndex: string;
   readonly thumbnailIndex: string;
 }
+
+export const enum OnWriteExistStrategy {
+  IGNORE,
+  REPLACE,
+}
diff --git a/src/app/shared/services/repositories/proof/proof.ts b/src/app/shared/services/repositories/proof/proof.ts
index bb39ff718..e0223b648 100644
--- a/src/app/shared/services/repositories/proof/proof.ts
+++ b/src/app/shared/services/repositories/proof/proof.ts
@@ -3,7 +3,10 @@ import { sortObjectDeeplyByKey } from '../../../../utils/immutable/immutable';
 import { MimeType } from '../../../../utils/mime-type';
 import { toDataUrl } from '../../../../utils/url';
 import { Tuple } from '../../database/table/table';
-import { ImageStore } from '../../image-store/image-store.service';
+import {
+  ImageStore,
+  OnWriteExistStrategy,
+} from '../../image-store/image-store.service';
 
 export class Proof {
   diaBackendAssetId?: string = undefined;
@@ -35,7 +38,11 @@ export class Proof {
   async setAssets(assets: Assets) {
     const indexedAssetEntries: [string, AssetMeta][] = [];
     for (const [base64, meta] of Object.entries(assets)) {
-      const index = await this.imageStore.write(base64, meta.mimeType);
+      const index = await this.imageStore.write(
+        base64,
+        meta.mimeType,
+        OnWriteExistStrategy.IGNORE
+      );
       indexedAssetEntries.push([index, meta]);
     }