Increasing size of cache and purging cache doesn't seem to have worked. Fault remains.

Thanks tipgundcp, I went to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer but where to from there to reset Cached Icons? Nearest I could find was :...

When photo folder is opened with thumbnail view (any size) initially the thumbnails show ok but then slowly the Portrait thumbnails have 2 white diagonal stripes placed over them this keeps going...