diff --git a/app/api/formsemestres.py b/app/api/formsemestres.py
index 24a98f338..afd2e9bad 100644
--- a/app/api/formsemestres.py
+++ b/app/api/formsemestres.py
@@ -13,12 +13,14 @@
   FormSemestre
 
 """
-import mimetypes
+import base64
+import io
 from operator import attrgetter, itemgetter
 
 from flask import g, make_response, request
 from flask_json import as_json
 from flask_login import current_user, login_required
+import PIL
 import sqlalchemy as sa
 import app
 from app import db, log
@@ -820,8 +822,8 @@ def formsemestre_get_description(formsemestre_id: int):
 @permission_required(Permission.ScoView)
 @as_json
 def formsemestre_edit_description(formsemestre_id: int):
-    """Modifie description externe du formsemestre
-
+    """Modifie description externe du formsemestre.
+    Les images peuvent êtres passées dans el json, encodées en base64.
     formsemestre_id : l'id du formsemestre
 
     SAMPLES
@@ -832,6 +834,10 @@ def formsemestre_edit_description(formsemestre_id: int):
     args = request.get_json(force=True)  # may raise 400 Bad Request
     if not formsemestre.description:
         formsemestre.description = FormSemestreDescription()
+    # Decode images (base64)
+    for key in ["image", "photo_ens"]:
+        if key in args:
+            args[key] = base64.b64decode(args[key])
     formsemestre.description.from_dict(args)
     db.session.commit()
     return formsemestre.description.to_dict()
@@ -868,11 +874,12 @@ def formsemestre_get_photo_ens(formsemestre_id: int):
     return _image_response(formsemestre.description.photo_ens)
 
 
-def _image_response(image_data):
+def _image_response(image_data: bytes):
     # Guess the mimetype based on the image data
-    mimetype = mimetypes.guess_type("image")[0]
-
-    if not mimetype:
+    try:
+        image = PIL.Image.open(io.BytesIO(image_data))
+        mimetype = image.get_format_mimetype()
+    except PIL.UnidentifiedImageError:
         # Default to binary stream if mimetype cannot be determined
         mimetype = "application/octet-stream"
 
diff --git a/app/views/notes_formsemestre.py b/app/views/notes_formsemestre.py
index 1bafa62da..e3e25c902 100644
--- a/app/views/notes_formsemestre.py
+++ b/app/views/notes_formsemestre.py
@@ -30,9 +30,11 @@ Emmanuel Viennet, 2023
 """
 
 import datetime
+import io
 
 from flask import flash, redirect, render_template, url_for
 from flask import current_app, g, request
+import PIL
 
 from app import db, log
 from app.decorators import (
@@ -319,6 +321,20 @@ def edit_formsemestre_description(formsemestre_id: int):
                                 scodoc_dept=g.scodoc_dept,
                             )
                         )
+                    try:
+                        _ = PIL.Image.open(io.BytesIO(image_data))
+                    except PIL.UnidentifiedImageError:
+                        flash(
+                            f"Image invalide ({field}), doit être une image",
+                            "danger",
+                        )
+                        return redirect(
+                            url_for(
+                                "notes.edit_formsemestre_description",
+                                formsemestre_id=formsemestre.id,
+                                scodoc_dept=g.scodoc_dept,
+                            )
+                        )
                     setattr(formsemestre_description, field, image_data)
 
             db.session.commit()
diff --git a/tests/api/setup_test_api.py b/tests/api/setup_test_api.py
index 2ce97eb88..126162e29 100644
--- a/tests/api/setup_test_api.py
+++ b/tests/api/setup_test_api.py
@@ -122,9 +122,14 @@ def GET(path: str, headers: dict = None, errmsg=None, dept=None, raw=False):
     if reply.headers.get("Content-Type", None) == "application/json":
         return reply.json()  # decode la reponse JSON
     if reply.headers.get("Content-Type", None) in [
-        "image/jpg",
-        "image/png",
         "application/pdf",
+        "application/vnd.ms-excel",
+        "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+        "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+        "image/gif",
+        "image/jpeg",
+        "image/png",
+        "image/webp",
     ]:
         retval = {
             "Content-Type": reply.headers.get("Content-Type", None),
@@ -132,7 +137,7 @@ def GET(path: str, headers: dict = None, errmsg=None, dept=None, raw=False):
         }
         return retval
     raise APIError(
-        "Unknown returned content {r.headers.get('Content-Type', None} !\n",
+        f"Unknown returned content {reply.headers.get('Content-Type', None)} !\n",
         status_code=reply.status_code,
     )
 
diff --git a/tests/api/test_api_formsemestre.py b/tests/api/test_api_formsemestre.py
index 923f4c799..1395a6a33 100644
--- a/tests/api/test_api_formsemestre.py
+++ b/tests/api/test_api_formsemestre.py
@@ -16,6 +16,7 @@ Utilisation :
     Lancer :
         pytest tests/api/test_api_formsemestre.py
 """
+import base64
 import json
 import requests
 from types import NoneType
@@ -813,6 +814,9 @@ def test_formsemestre_description(api_admin_headers):
     assert r["salle"] == "une salle"
     assert r["dispositif"] == 1
     assert r["wip"] is True
+    # La réponse ne contient pas les images, servies à part:
+    assert "image" not in r
+    assert "photo_ens" not in r
     r = POST(
         f"/formsemestre/{formsemestre_id}/description/edit",
         data={
@@ -828,3 +832,15 @@ def test_formsemestre_description(api_admin_headers):
     assert r["salle"] == ""
     assert r["dispositif"] == 0
     assert r["wip"] is False
+    # Upload image
+    with open("tests/ressources/images/papillon.jpg", "rb") as f:
+        img = f.read()
+    img_base64 = base64.b64encode(img).decode("utf-8")
+    r = POST(
+        f"/formsemestre/{formsemestre_id}/description/edit", data={"image": img_base64}
+    )
+    assert r["wip"] is False
+    r = GET(f"/formsemestre/{formsemestre_id}/description/image", raw=True)
+    assert r.status_code == 200
+    assert r.headers.get("Content-Type") == "image/jpeg"
+    assert r.content == img