I had done a set up on the server to store the images in an external path (library > FilemakerServer> Data > Documents >RC_Data_FMS >"FileName" > Files > "FileName" > "TableName" > "Container FieldName" > ) .
But when I closed the files and removed data file from the server and uploaded the same data file on the server again. Allen the images stored in the above path are gone.
Most dreadful thing is , while removing a file , it does not show you any warning regrading the removal of container data from the external path.
Usually it is impossible to take back up of the folder from admin console as , no filemaker files present on folder.