Thanks!
 after a little search for "image hosting" I have found Photobucket.com (Photobasket.com does no more exist) and succeeded in fixing the question. By the way I continue to not really understand why Renderosity doesn't host the thumbnails for freestuff (after all they are images like those we upload in the galleries and they are even smaller!). I understand for the zip files which can be quite large, but why not for thumbnail (maybe as an option when uploading images). Such a possibility would give the freestuff area a much cleaner presentation.