--- a/sat/core/constants.py	Sun Mar 01 18:33:16 2020 +0100
+++ b/sat/core/constants.py	Sun Mar 01 18:47:05 2020 +0100
@@ -370,13 +370,6 @@
     # internationalisation
     DEFAULT_LOCALE = "en_GB"
 
-    # Contexts
-    # context indicate how things are done (e.g. to who/what a file is transfered)
-    # this is useful to make some decision (e.g. image size)
-
-    # something is done in instant messaging
-    CONTEXT_CHAT = "CONTEXT_CHAT"
-
     ## Misc ##
     SAVEFILE_DATABASE = APP_NAME_FILE + ".db"
     IQ_SET = '/iq[@type="set"]'

--- a/sat/tools/images.py	Sun Mar 01 18:33:16 2020 +0100
+++ b/sat/tools/images.py	Sun Mar 01 18:47:05 2020 +0100
@@ -21,27 +21,27 @@
 
 import tempfile
 from PIL import Image
-from sat.core.constants import Const as C
 from pathlib import Path
 from twisted.internet import threads
 
 
-def checkImage(host, path, context=C.CONTEXT_CHAT):
+def checkImage(host, path, max_size=None):
     """Analyze image and return a report
 
     report will indicate if image is too large, and the recommended new size if this is
     the case
     @param host: SàT instance
     @param path(str, pathlib.Path): image to open
-    @param context(str): context in which the image is transfered
+    @param max_size(tuple[int, int]): maximum accepted size of image
+        None to use value set in config
     @return dict: report on image, with following keys:
         - too_large: true if image is oversized
         - recommended_size: if too_large is True, recommended size to use
     """
-    # TODO: context is not used yet
     report = {}
     image = Image.open(path)
-    max_size = tuple(host.memory.getConfig(None, "image_max", (1200, 720)))
+    if max_size is None:
+        max_size = tuple(host.memory.getConfig(None, "image_max", (1200, 720)))
     if image.size > max_size:
         report['too_large'] = True
         if image.size[0] > max_size[0]:
@@ -57,21 +57,32 @@
     return report
 
 
-def _resizeImageBlocking(image_path, new_size):
+def _resizeImageBlocking(image_path, new_size, dest=None):
     im_path = Path(image_path)
     im = Image.open(im_path)
     resized = im.resize(new_size, Image.LANCZOS)
-    with tempfile.NamedTemporaryFile(suffix=im_path.suffix, delete=False) as f:
+
+    if dest is None:
+        dest = tempfile.NamedTemporaryFile(suffix=im_path.suffix, delete=False)
+    elif isinstance(dest, Path):
+        dest = Path.open('wb')
+
+    with dest as f:
         resized.save(f, format=im.format)
+
     return Path(f.name)
 
 
-def resizeImage(image_path, new_size):
-    """Resize an image to a new temporary file, and return it path
+def resizeImage(image_path, new_size, dest=None):
+    """Resize an image to a new file, and return its path
 
     @param image_path(str, Path): path of the original image
     @param new_size(tuple[int, int]): size to use for new image
-    @return (Path): path of the resized file. The image at this path must be deleted
-        after use
+    @param dest(None, Path, file): where the resized image must be stored, can be:
+        - None: use a temporary file
+        - Path: path to the file to create/overwrite
+        - file: a file object which must be opened for writing in binary mode
+    @return (Path): path of the resized file.
+        The image at this path should be deleted after use
     """
-    return threads.deferToThread(_resizeImageBlocking, image_path, new_size)
+    return threads.deferToThread(_resizeImageBlocking, image_path, new_size, dest)