Please provide links to "the solutions that" you "found but it's not working" so we don't repeat ourselves.
When you describe something like "by changing upload path" please indicate the before and after path and any/all errors, warnings, etc.
Same goes for "change the .htaccess to this." What was it before the change? I THINK the RewriteRule and link you provided would result in your server looking for
Does the link to the .jpg you posted above, indicate the physical path? ie. In an FTP client the path is /files/2013/03/choisir_site_de_rencontre1-150x150.jpg