i just downloaded the image
openSUSE-Tumbleweed-GNOME-Live-x86_64-Snapshot20171107-Media.iso
from 2 different locations:
1 main page: http://download.opensuse.org/tumbleweed/iso/openSUSE-Tumbleweed-GNOME-Live-x86_64-Current.iso
2 mirror: http://ftp.icm.edu.pl/pub/Linux/opensuse/tumbleweed/iso/openSUSE-Tumbleweed-GNOME-Live-x86_64-Snapshot20171107-Media.iso
i also downloaded sha256 from main page: http://download.opensuse.org/tumbleweed/iso/openSUSE-Tumbleweed-GNOME-Live-x86_64-Current.iso.sha256
gpg signatures are ok, but checksums are wrong
wrong sums stated in files: 8c5a546c387ab61bdedb9ea7e03604f1bd00a8cb5c729e9894beb1b8919f9878
but in fact they are e9468e6691c0da799c5c4b841f400321eee50a2d669ebddb97c8280ff1b5c015 as stated on non ssl mirror page: http://download.opensuse.org/tumbleweed/iso/openSUSE-Tumbleweed-GNOME-Live-x86_64-Snapshot20171107-Media.iso?mirrorlist
but the mirror page provides just sha256 with any signature