STM32 + LwIP where are the FS files and how to modify these ?

[Ciuffoly]

I am able to compile and modify the LwIP example but where are the FS file and how to modify these and upload on STM32F746-DISCO ?

file httpserver-netconn.c
 
 
 if ((buflen >=5) && (strncmp(buf, "GET /", 5) == 0))
 {
 /* Check if request to get ST.gif */ 
 if (strncmp((char const *)buf,"GET /STM32F7xx_files/ST.gif",27)==0) 
 {
 fs_open(&file, "/STM32F7xx_files/ST.gif"); <<<<<<<<<<<<<<<<<<<< ?
 netconn_write(conn, (const unsigned char*)(file.data), (size_t)file.len, NETCONN_NOCOPY);
 fs_close(&file);
 } 
 ..................
 else if(strncmp(buf, "GET /stat.html", 14) == 0)
 {
 DynWebPage(conn);
 }
 else if(strncmp(buf, "GET /SELECT_OPT", 15) == 0)
 {
 	LCD_LOG_State("Received a change to Optical ");
 	buttonOPTClicked();
 	sendOK(conn);
 }
 else if(strncmp(buf, "GET /SELECT_AES", 15) == 0)
 {
 	LCD_LOG_State("Received a change to AES-ABU ");
 	buttonAESClicked();
 	sendOK(conn);
 }