diff --git a/gazu/asset.py b/gazu/asset.py
index 9614e1e..1752609 100644
--- a/gazu/asset.py
+++ b/gazu/asset.py
@@ -169,6 +169,7 @@ def new_asset(
     description=None,
     extra_data={},
     episode=None,
+    is_shared=False,
     client=default,
 ):
     """
@@ -181,6 +182,7 @@ def new_asset(
         description (str): Additional information.
         extra_data (dict): Free field to add any kind of metadata.
         episode (str / dict): The episode this asset is linked to.
+        is_shared (bool): True if asset is shared between multiple projects.
 
     Returns:
         dict: Created asset.
@@ -189,7 +191,7 @@ def new_asset(
     asset_type = normalize_model_parameter(asset_type)
     episode = normalize_model_parameter(episode)
 
-    data = {"name": name, "data": extra_data}
+    data = {"name": name, "data": extra_data, "is_shared": is_shared}
 
     if description is not None:
         data["description"] = description
diff --git a/gazu/files.py b/gazu/files.py
index edfbe9f..532efb3 100644
--- a/gazu/files.py
+++ b/gazu/files.py
@@ -147,7 +147,7 @@ def get_preview_file(preview_file_id, client=default):
     return raw.fetch_one("preview-files", preview_file_id, client=client)
 
 
-def remove_preview_file(preview_file, client=default):
+def remove_preview_file(preview_file, force=False, client=default):
     """
     Remove given preview file from database.
 
@@ -155,8 +155,12 @@ def remove_preview_file(preview_file, client=default):
         preview_file (str / dict): The preview_file dict or ID.
     """
     preview_file = normalize_model_parameter(preview_file)
+    params = {}
+    if force:
+        params = {"force": True}
     return raw.delete(
         "data/preview-files/%s" % preview_file["id"],
+        params=params,
         client=client,
     )
 
diff --git a/gazu/task.py b/gazu/task.py
index 1796409..a455e83 100644
--- a/gazu/task.py
+++ b/gazu/task.py
@@ -675,13 +675,15 @@ def remove_task(task, client=default):
     raw.delete("data/tasks/%s" % task["id"], {"force": True}, client=client)
 
 
-def start_task(task, started_task_status=None, client=default):
+def start_task(task, started_task_status=None, person=None, client=default):
     """
     Create a comment to change task status to started_task_status
     (by default WIP) and set its real start date to now.
 
     Args:
         task (str / dict): The task dict or the task ID.
+        started_task_status (str / dict): The task status dict or ID.
+        person (str / dict): The person dict or the person ID.
 
     Returns:
         dict: Created comment.
@@ -700,7 +702,7 @@ def start_task(task, started_task_status=None, client=default):
                 )
             )
 
-    return add_comment(task, started_task_status, client=client)
+    return add_comment(task, started_task_status, person=person, client=client)
 
 
 def task_to_review(