I have that problem 50% of the time, just lost 2h of play because of it, please fix it !! I'm not the only one, there's a thread someone started on AHQ. It's been going on for a while and started again since the last patch.
Here's the thread, please click "Me too" if you also have the problem.
https://answers.ea.com/t5/Technical-Issues-Mac/Sims-4-keeps-crashing-when-accessing-the-Gallery/td-p/8027593/highlight/false
Comments
It's a problem with your machine I think rather than EA's. I think SimGuruNick or Answers HQ might help but they need this.
Windows version....from their site..
Open and run DxDiag.exe
This tool is used to collect info about devices to help troubleshoot problems with DirectX sound and video. A support person might ask for this info, or you might post it in a forum when you ask for help.
In Windows, select Start
Windows logo Start button
and enter dxdiag into the search box on the taskbar. Select dxdiag from the results.
In the tool, select Save All Information for an easily shared format.
(Could be just that your machine needs a clean and overheats and crashes because of dust).