Yeah, this is a current design problem in Construct. Everything's loaded in on startup. If you have a graphics card with loads of VRAM, it's not an issue, but it's obviously a problem for low end machines. The next major build will include controls so you can only load in to VRAM what's currently on-screen. That should help!
Also, it shouldn't just crash if you exceed VRAM - it ought to give you an error message saying that's what happened, so you know. I thought that would be working, I'll double check the code for it...