After I insert a Graphic, Calc crashes and reboot, trying to restore the file. Repeating the action makes same error. Closed all programs and same thing. It stands for 2 seconds with the graphic on the sheet before crashing.
There were very similar bug reports, like bug 94209 and bug 100812, so I'm closing this as duplicate. Should be fixed in LibreOffice 5.2.0.4. There's also been an update in the 5.1 branch since then, 5.1.5.2, no one gave feedback about that release, but it might be worth checking that one out. *** This bug has been marked as a duplicate of bug 94209 ***
Update to 5.2.0.4 solved my issue. Thanks guys.