You could try to open the images with file_open_read and read the content into a String, then send the string to a 3DGS Server application and save it as a file with str_open_write. If clients connects to the server than you could send the image in the same way to the clients.
Viruses are really a problem, but without a implementet virus search engine in 3DGS you can't really be sure to avoid them.