[cOuNtErFiET]

you have to have an FTP account created, and an FTP client then you can just use that to send the image to the server then just have to link it, if you dont have acp access then you cannot create an ftp account.

if you have an ftp account then all you need to do is get an ftp client and enter you login info then navigate to the right folder and upload the image then link it

or if you just have acp access you can just add it from the File Manager in cpanel if you use that, i use cPanel so idk other hosts might not have chosen to use cpanel but thats neither here nor there, first priority is to find out if you have ACP Access or an FTP account access