diff --git a/dags/image_transfer.py b/dags/image_transfer.py
index 02e764fefba9ecfa1e11c3822001414c1ee82c08..ba2da0642cbc4d2a517af7152e06943316ca7079 100644
--- a/dags/image_transfer.py
+++ b/dags/image_transfer.py
@@ -11,7 +11,12 @@ default_args = {
     'owner': 'airflow',
 }
 
-
+def file_exist(sftp, name):
+    try:
+        r = sftp.stat(name)  
+        return r.st_size
+    except:
+        return -1
 
 @dag(default_args=default_args, schedule_interval=None, start_date=days_ago(2), tags=['example'])
 def transfer_image():
@@ -28,10 +33,19 @@ def transfer_image():
 
         with ssh_hook.get_conn() as ssh_client:
             sftp_client = ssh_client.open_sftp()
+            remote_name = os.path.join(target, image_id)
+            size = file_exist(sftp=sftp_client, name=remote_name)
+            if size>0:
+                print(f"File {remote_name} exists and has {size} bytes")
+                force = params.get('force', True)
+                if force!= True:
+                    return 0
+                print("Forcing overwrite")
+
             ssh_client.exec_command(command=f"mkdir -p {target}")
             
             with requests.get(url, stream=True, verify=False) as r:
-                with sftp_client.open(os.path.join(target, image_id), 'wb') as f:
+                with sftp_client.open(remote_name, 'wb') as f:
                     f.set_pipelined(pipelined=True)
                     while True:
                         chunk=r.raw.read(1024 * 1000)
diff --git a/docs/apirequests.adoc b/docs/apirequests.adoc
index d3276c76bb3e9c721bc085b9d5e6c720d371131e..3b5d9a6b8f14075ca580d7166e924fd9c2454a14 100644
--- a/docs/apirequests.adoc
+++ b/docs/apirequests.adoc
@@ -118,7 +118,7 @@ Optionally, the record created in b2share can be registered with data cat. This
 To transfer images from eFlows4HPC image build service use dag defined in +dags/image_transfer.py+ (transfer_image). It requires two parameters +image_id+ name of the image in the image
 build service (e.g. "wordcount_skylake.sif") and +target+ which defines a path on the system where the image will be transfered to. 
 
-The parameters should be passed along the credentials as described in <<credentials>>. The target directory will be created with ``mkdir -p`` on the target machine. The image is streamed directly to the target location (no local copy on DLS worker).
+The parameters should be passed along the credentials as described in <<credentials>>. The target directory will be created with ``mkdir -p`` on the target machine. The image is streamed directly to the target location (no local copy on DLS worker). By default the file on the target location will be overwritten, this can be disabled by providing +force='false'+ as dag parameter.  
 
 ----
 curl -X POST -u USER:PASS -H "Content-Type: application/json" \