Comment 12 for bug 1665602

I don't had the problem with an old install from: Ubuntu 17.04 "Zesty Zapus" - Alpha amd64 (20161106)
so I'm trying to give some more info.

I started with:

Ubuntu installed from: Ubuntu 17.04 "Zesty Zapus" - Alpha amd64 (20161106)
NEVER updated:
corrado@corrado-z-nov16:~$ uname -a
Linux corrado-z-nov16 4.10.0-8-generic #10-Ubuntu SMP Mon Feb 13 14:04:59 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
corrado@corrado-z-nov16:~$

attached: BeforeUpdates: log .cache .config .local inxi screenshot
thumbnails where created ok - see screenshot

Then I Run apt-get update + upgrade

attached: After1stUpdate: installer Pictures .cache .config .gconf .local varous logs
thumbnails created wrong. see last 2 thumbnails

I restarted, but ubuntu started in low graphic mode. Restarted in emergency mode. Run update + upgrade + dist-upgrade. attached: 2ndUpgrade: varoius logs.

Restart again. now all seems ok BUT thumbnails are wrong.
attached: AfterLastUpgrade: a lot of data. thumbnails wrong for .jpg and .png. Good thumbnail for .tiff

I still have a copy of the old iso: Ubuntu 17.04 "Zesty Zapus" - Alpha amd64 (20161106)
so I may reistall it and produce more doc.
Let my know if You need.
bye