Following your instructions, I don't get the crash you describe. I also tried by selecting other image tools before attempting import but still didn't crash.
Are the steps you describe complete?
Using same 64bit OS and C2 version.
I checked again and it still happens. This is what i exactly did.
1. Create a new empty project.
2. Right click, and choose "Insert new object". Choose sprite and click on the canvas.
3. With the object opened, click on the "Rectangle Select".
4. In the animations frames pan, right click and choose "import frames" > "from spritstrip". Select a file and open.
It should hang after. It does it to me all the time. Hmm