Transfering small files problem

Hi,

Is there a known problem with small files transfer with lftp?
I have this strange behavior: when transfering small JPG files
(thumbnails of larger photos), lftp hangs for several minutes, and the
resulting file is several times bigger than the original (3 to 4 KB).
I have no problem transfering bigger files (such as the original
photos which are 80 to 120KB).
And using the konqueror ftp works fine with these small files, so it
seems the problem is with lftp.

I use Kubuntu, with :
LFTP | Version 3.5.6 | Copyright (c) 1996-2006 Alexander V. Lukyanov
Readline 5.2, GnuTLS 1.4.4, zlib 1.2.3

Thanks for your help
Yann