diff --git a/TODO.md b/TODO.md
index be9a789..b60e289 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,3 +1,4 @@
 - Parametrize bot API url in env variable
-- Encode images in base64
-- Parametrize tags
\ No newline at end of file
+- Encode images in base64 with proper prefix "data:image/png;base64,<encoding>"
+- Parametrize tags
+- Generalize the ImageService test with faker
\ No newline at end of file
diff --git a/src/services/ImageService.ts b/src/services/ImageService.ts
index 2b8ca37..6b47e37 100644
--- a/src/services/ImageService.ts
+++ b/src/services/ImageService.ts
@@ -5,7 +5,7 @@ import GelbooruApiService from "./GelbooruApiService";
 
 class ImageService {
     postsQueue: Image[] = [];
-    
+
     async get(): Promise<Image> {
         while (this.postsQueue.length === 0) {
             const validPosts = await this.getNewValidImages();
@@ -21,12 +21,24 @@ class ImageService {
         const botResponse = await BotApiService.getAll();
         const imagesUrls = botResponse.images.map(image => image.url);
 
-        const validPosts = posts
+        const validPosts = Promise.all(posts
             .filter(post => !imagesUrls.some(url => url === post.url))
-            .map(post => ({ url: post.url, tags: post.tags, content: "TODO" }));
-
+            .map(async (post): Promise<Image> => {
+                const imageData = await this.urlToImageData(post.url);
+                const encodedImage = this.imageToBase64(imageData);
+                return { url: post.url, tags: post.tags, content: encodedImage };
+            }));
+        
         return validPosts;
     }
+
+    private async urlToImageData(url: string): Promise<string> {
+        return await (await fetch(url)).text();
+    }
+
+    private imageToBase64(imageData: string): string {
+        return Buffer.from(imageData, "binary").toString("base64");
+    }
 }
 
 export default new ImageService();
\ No newline at end of file
diff --git a/test/ImageService.test.ts b/test/ImageService.test.ts
deleted file mode 100644
index 6b9381a..0000000
--- a/test/ImageService.test.ts
+++ /dev/null
@@ -1,41 +0,0 @@
-import { describe, expect, it, mock } from "bun:test";
-import Image from "../src/types/Image";
-import ImageService from "../src/services/ImageService";
-import GelbooruApiResponse from "../src/types/GelbooruServiceResponse";
-import { BotApiResponse } from "../src/types/BotApiResponse";
-
-describe("endpoint gets a non repeated image", () => {
-    it("should return an image that is not in the response of the /images endpoint of the bot API", async () => {
-        const REPEATED_URL = "image.com/1";
-        const UNIQUE_URL = "image.com/2";
-
-        mock.module("../src/services/GelbooruApiService", () => {
-            let alreadyCalled = false;
-            return {
-                default: {
-                    get: (): GelbooruApiResponse => {
-                        if (alreadyCalled) {
-                            return { posts: [{ url: UNIQUE_URL, tags: [] }] };
-                        } else {
-                            alreadyCalled = true;
-                            return { posts: [{ url: REPEATED_URL, tags: [] }] };
-                        }
-                    }
-                }
-            }
-        });
-
-        mock.module("../src/services/BotApiService", () => ({
-            default: {
-                getAll: (): BotApiResponse => ({
-                    images: [
-                        { _id: "0", url: REPEATED_URL, status: "consumed", tags: ["pokemon", "computer"], "__v": 0 }
-                    ]
-                })
-            }
-        }));
-
-        const image: Image = await ImageService.get();
-        expect(image.url).not.toBe(REPEATED_URL);
-    })
-})
\ No newline at end of file
diff --git a/test/ImageService/ImageService.test.ts b/test/ImageService/ImageService.test.ts
new file mode 100644
index 0000000..359a131
--- /dev/null
+++ b/test/ImageService/ImageService.test.ts
@@ -0,0 +1,54 @@
+import { describe, expect, it, mock, spyOn } from "bun:test";
+import Image from "../../src/types/Image";
+import ImageService from "../../src/services/ImageService";
+import GelbooruApiResponse from "../../src/types/GelbooruServiceResponse";
+import { BotApiResponse } from "../../src/types/BotApiResponse";
+import fs from "node:fs";
+
+describe("endpoint gets a non repeated image", () => {
+    it("should return an image that is not in the response of the /images endpoint of the bot API", async () => {
+        const REPEATED_URL = "https://fastly.picsum.photos/id/1/10/20.jpg?hmac=gY6PvUXFacKfYpBpTTVcNLxumpyMmoCamM-J5DOPwNc";
+        const UNIQUE_URL = "https://fastly.picsum.photos/id/2/10/20.jpg?hmac=zy6lz21CuRIstr9ETx9h5AuoH50s_L2uIEct3dROpY8";
+
+        mock.module("../../src/services/GelbooruApiService", () => {
+            let alreadyCalled = false;
+            return {
+                default: {
+                    get: (): GelbooruApiResponse => {
+                        if (alreadyCalled) {
+                            return { posts: [{ url: UNIQUE_URL, tags: [] }] };
+                        } else {
+                            alreadyCalled = true;
+                            return { posts: [{ url: REPEATED_URL, tags: [] }] };
+                        }
+                    }
+                }
+            }
+        });
+
+        mock.module("../../src/services/BotApiService", () => ({
+            default: {
+                getAll: (): BotApiResponse => ({
+                    images: [
+                        { _id: "0", url: REPEATED_URL, status: "consumed", tags: ["pokemon", "computer"], "__v": 0 }
+                    ]
+                })
+            }
+        }));
+
+        const image: Image = await ImageService.get();
+        expect(image.url).not.toBe(REPEATED_URL);
+    });
+});
+
+describe("imageToBase64 works as expected", () => {
+    it("should encode image to base64 properly", () => {
+        const imageData = fs.readFileSync('./test/ImageService/testImage.jpg');
+        const imageToBase64Spy = spyOn(ImageService as any, 'imageToBase64');
+        
+        const actualEncoding = imageToBase64Spy.call(ImageService, imageData);
+        const expectedEncoding = fs.readFileSync('./test/ImageService/testImage.b64', "base64").toString();
+
+        expect(actualEncoding).toBe(expectedEncoding);
+    })
+})
\ No newline at end of file
diff --git a/test/ImageService/testImage.b64 b/test/ImageService/testImage.b64
new file mode 100644
index 0000000..c559d97
--- /dev/null
+++ b/test/ImageService/testImage.b64
@@ -0,0 +1 @@
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
\ No newline at end of file
diff --git a/test/ImageService/testImage.jpg b/test/ImageService/testImage.jpg
new file mode 100644
index 0000000..90ec4fa
Binary files /dev/null and b/test/ImageService/testImage.jpg differ