diff --git a/backend/src/main/java/pdl/backend/ImageDao.java b/backend/src/main/java/pdl/backend/ImageDao.java
index 32acdc9..9b0c660 100644
--- a/backend/src/main/java/pdl/backend/ImageDao.java
+++ b/backend/src/main/java/pdl/backend/ImageDao.java
@@ -16,21 +16,23 @@ import org.springframework.stereotype.Repository;
 @Repository
 public class ImageDao implements Dao<Image> {
 
+	private final static String[] ACCEPTED_EXTENSION = { "jpg", "png", "jpeg" };
+
 	private final Map<Long, Image> images = new HashMap<>();
 
-	public ImageDao() {
-		try {
-			final var folderPath = new ClassPathResource("images");
-			if (!folderPath.exists())
-				throw new ImageResourceMissingException("folder images doesn't not exsit");
-			final var folder = folderPath.getFile();
-			getAllImages(folder);
-		} catch (final Exception e) {
-			e.printStackTrace();
-		}
+	public ImageDao() throws IOException {
+		this("images");
 	}
 
-	public void getAllImages(final File folder) {
+	public ImageDao(final String folderPathStr) throws IOException {
+		final var folderPath = new ClassPathResource(folderPathStr);
+		if (!folderPath.exists())
+			throw new ImageResourceMissingException("folder images doesn't not exist");
+		final var folder = folderPath.getFile();
+		getAllImages(folder);
+	}
+
+	private void getAllImages(final File folder) {
 		for (final File file : folder.listFiles()) {
 			if (file.isDirectory()) {
 				getAllImages(file);
@@ -41,7 +43,14 @@ public class ImageDao implements Dao<Image> {
 				if (i > 0) {
 					extension = file.getName().substring(i + 1);
 				}
-				if (!extension.equals("jpg") && !extension.equals("png")) {
+				boolean accepted = false;
+				for (final String ext : ACCEPTED_EXTENSION) {
+					if (ext.equals(extension)) {
+						accepted = true;
+						break;
+					}
+				}
+				if (!accepted) {
 					continue;
 				}
 				byte[] fileContent;
diff --git a/backend/src/main/resources/images/imagesAnimals/birds.jpg b/backend/src/main/resources/images/imagesAnimals/birds.png
similarity index 100%
rename from backend/src/main/resources/images/imagesAnimals/birds.jpg
rename to backend/src/main/resources/images/imagesAnimals/birds.png
diff --git a/backend/src/main/resources/imagesTest/aube.jpeg b/backend/src/main/resources/imagesTest/aube.jpeg
new file mode 100644
index 0000000..dd38f75
Binary files /dev/null and b/backend/src/main/resources/imagesTest/aube.jpeg differ
diff --git a/backend/src/main/resources/imagesTest/imagesAnimals/birds.png b/backend/src/main/resources/imagesTest/imagesAnimals/birds.png
new file mode 100644
index 0000000..38bae8d
Binary files /dev/null and b/backend/src/main/resources/imagesTest/imagesAnimals/birds.png differ
diff --git a/backend/src/main/resources/imagesTest/imagesAnimals/lion.txt b/backend/src/main/resources/imagesTest/imagesAnimals/lion.txt
new file mode 100644
index 0000000..8b42025
--- /dev/null
+++ b/backend/src/main/resources/imagesTest/imagesAnimals/lion.txt
@@ -0,0 +1 @@
+LION
\ No newline at end of file
diff --git a/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/GUITARE.txt b/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/GUITARE.txt
new file mode 100644
index 0000000..7f27c64
--- /dev/null
+++ b/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/GUITARE.txt
@@ -0,0 +1 @@
+GUITARE
\ No newline at end of file
diff --git a/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/Piano/DONOTREADME.md b/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/Piano/DONOTREADME.md
new file mode 100644
index 0000000..834b4fc
--- /dev/null
+++ b/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/Piano/DONOTREADME.md
@@ -0,0 +1 @@
+# BOO
\ No newline at end of file
diff --git a/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/Piano/poppy.jpg b/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/Piano/poppy.jpg
new file mode 100644
index 0000000..6ad663a
Binary files /dev/null and b/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/Piano/poppy.jpg differ
diff --git a/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/mountains.jpg b/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/mountains.jpg
new file mode 100644
index 0000000..afa645d
Binary files /dev/null and b/backend/src/main/resources/imagesTest/imagesAnimals/oueoueoue/mountains.jpg differ
diff --git a/backend/src/main/resources/imagesTest/test.jpg b/backend/src/main/resources/imagesTest/test.jpg
new file mode 100644
index 0000000..bb7b4da
Binary files /dev/null and b/backend/src/main/resources/imagesTest/test.jpg differ
diff --git a/backend/src/test/java/pdl/backend/ImageDaoTests.java b/backend/src/test/java/pdl/backend/ImageDaoTests.java
new file mode 100644
index 0000000..7b654de
--- /dev/null
+++ b/backend/src/test/java/pdl/backend/ImageDaoTests.java
@@ -0,0 +1,28 @@
+package pdl.backend;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.io.IOException;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+public class ImageDaoTests {
+
+	@Test
+	@DisplayName("ImageDao should throw an exception when the image folder is missing")
+	public void exceptionImageFolderNotFound() throws Exception {
+		assertThrows(IOException.class, () -> {
+			new ImageDao("testing");
+		});
+	}
+
+	@Test
+	@DisplayName("ImageDao should have all images of the folder / subfolders and should ignore non (JPG/PNG) files")
+	public void initImageDao() throws Exception {
+		ImageDao imageDao = new ImageDao("imagesTest");
+		var listImages = imageDao.retrieveAll();
+		assert (listImages.size() == 5);
+	}
+}
\ No newline at end of file