My desktop icons are huge!

I picked up my keyboard roughly and may have accidentally changed my desktop icon size through some mysterious key combination. My desktop icons on the conventional desktop are all huge but under display > change size of all items I can only make them LARGER. Even setting an icon size manually will not make them reasonably small.
 
Problem is fixed. I restarted in safe mode and then did a system restore and when it was finished I got a message saying that 'system restore had failed and nothing had been changed' yet my icons were normal again! This was my third attempt at a system restore, each time it failed, but this was my first attempt in safe mode, go figure. I think maybe merely entering safe mode was the fix and system restore had nothing to do with it.