CopyAttachmentsFromOneItemToOther

 /// <summary>
        /// Method that copies attachments from one item to another
        /// </summary>
        /// <param name="currentWeb">Current web object</param>
        /// <param name="sourceListName">The name of the list in which the source item is available</param>
        /// <param name="targetListName">The name of the list in which the target item is available, provide the name even if both the source and target list are the same</param>
        /// <param name="sourceItemId">Item id of the source item</param>
        /// <param name="targerItemId">Item id of the target item</param>
        /// <returns>Boolean value</returns>
        public static bool CopyAttachmentsFromOneItemToOther(SPWeb currentWeb, string sourceListName, string targetListName, int sourceItemId, int targerItemId)
        {
            bool operationComplete = false;

            try
            {
                SPAttachmentCollection attachmentCollection = null;

                SPSecurity.RunWithElevatedPrivileges(delegate()
                 {
                     currentWeb.AllowUnsafeUpdates = true;
                     SPList sourceList = currentWeb.Lists.TryGetList(sourceListName);
                     SPList targetList = currentWeb.Lists.TryGetList(targetListName);

                     if (sourceList != null)
                     {
                         SPListItem targetItem = null;
                         SPListItem sourceItem = sourceList.Items.GetItemById(sourceItemId);
                         if (targetList != null)
                         {
                             targetItem = targetList.Items.GetItemById(targerItemId);
                         }

                         if (sourceItem != null && targetItem != null)
                         {
                             attachmentCollection = sourceItem.Attachments;
                             if (attachmentCollection.Count > 0)
                             {
                                 foreach (string fileName in sourceItem.Attachments)
                                 {
                                     SPFile file = sourceItem.ParentList.ParentWeb.GetFile(sourceItem.Attachments.UrlPrefix + fileName);
                                     StreamReader fsReader = new StreamReader(file.OpenBinaryStream());
                                     byte[] contents = null;
                                     using (Stream fStream = fsReader.BaseStream)
                                     {
                                         contents = new byte[fStream.Length];

                                         fStream.Read(contents, 0, (int)fStream.Length);

                                         fStream.Close();
                                     }
                                    // byte[] fileData = file.OpenBinary();
                                     targetItem.Attachments.Add(fileName, contents);                                   
                                 }
                                 targetItem.Update();
                             }
                         }
                     }
                     else
                     {
                         LoggingService.WriteExceptionsToLog("Common", Constants.FORMATTEDERRORMESSAGE, "CopyAttachmentsFromOneItemToOther","","");
                         operationComplete = false;
                     }
                 });
            }
            catch (Exception ex)
            {
                operationComplete = false;
                LoggingService.WriteExceptionsToLog("Common", Constants.FORMATTEDERRORMESSAGE, "CopyAttachmentsFromOneItemToOther", ex.Message, ex.StackTrace);
                throw;
            }
            finally
            {
                currentWeb.AllowUnsafeUpdates = false;
            }

            return operationComplete;
        }