How upload files to protected directories?

Hello I post my question here because I can't understand what host support is trying to say to me: I use paid host with PHP and MySql facilities, all working fine for me (both PHP and MySql). I offer to customers ability for storing updating and retrieving MySql records using <form POST ..> HTML commands. My problem begins when I want customers also be allowed to upload images (.GIF and .JPG files) linked to their records. If possible, I would prefer store these images into BLOB MySql fields and then show image stream using PHP GD functions, but this appears difficult because host PHP doesn't have GD library. Next solution is to store GIF/JPG files into some directory and then use html commands to show pictures. But POST commands are denied on this host (as well as ftp commands) because they don't want somebody uploading trojan programs there. Support said to me: "the only way around this is to write a cgi script which uploads/writes to a file - there are commercial products that do this safely or maybe you can find a free script on one of the many cgi script sites - most commercial classified ad scripts have a function such as this." Does somebody know what this means?. If ftp commands and all PHP filesystem commands are disallowed, how could CGI script solve it? And also, what are 'classified ad scripts'? Sorry I live in Brazil and don't catch all english expressions: are these scripts to post classified ads? Any other solution will be welcome. Thanks in advance Mig