File stopping upload of Artful website updates (RW 8.6.2)

I’ve never had a problem uploading files via FTP to server via Dropbox, but now there is a file stopping upload. I located it in data and it is an old photo, so I removed it from RW (Artful), and put it in Trash, ( although I haven’t emptied Trash) but obviously it is still somewhere as that file is still stopping upload, then RW crashes. I’ve tried to go back to an earlier RW file for website but that doesn’t work. My server said to compress file and use File Zilla. I haven’t tried that yet, as would prefer to stay with how I was doing it these past years. Any clues how to eliminate troublemaking file? Thanks in advance!