diff --git a/src/Piwigo.Client/PiwigoClientExtensions.cs b/src/Piwigo.Client/PiwigoClientExtensions.cs
index d0265c0..a3e48c3 100644
--- a/src/Piwigo.Client/PiwigoClientExtensions.cs
+++ b/src/Piwigo.Client/PiwigoClientExtensions.cs
@@ -51,7 +51,7 @@ public static class PiwigoClientExtensions
         }
 
         var supportedFileTypes = await client.Session.GetSupportedFileTypes(cancellationToken);
-        if (!supportedFileTypes.Contains(imageToUpload.Extension.ToLower()))
+        if (!supportedFileTypes.Contains(imageToUpload.Extension.Replace(".", string.Empty).ToLower()))
         {
             throw new PiwigoException(
                 $"The file {imageToUpload.Name} has extension {imageToUpload.Extension} which is not supported by the connected piwigo server. Please use one of the following formats {string.Join(",", supportedFileTypes)}");