Where is this thumbnail cache coming from, is it normal?

CCleaner for Windows
1

I have been running CCleaner a bit obsessively these days, and I have been noticing that once in awhile my thumbnail cache has been going up to three megabytes-ish without me opening any image folders. I continuously clean it, but it comes back every so often. I even used regedit to disable thumbnail cache, but I keep getting 3 Mb or so of it every so often.

Malwarebytes and McAfee say I am clean. I just want to confirm that this is normal

Thanks

2

It's probably normal. All icons get cached as thumbs too, I think (someone correct me if I'm wrong)