Interior and TIF

Was the day at my daughters and we'd set out to take some pix of her home's interior as she wanted to get the idea of how it should look when she and her man put their flat up for sale next year. We had a few hours to go about, while her son was in school.

When back home I downloaded the pix from my card and noticed they were registered as TIF files and not as NEF and JPG files. I haven't got a clue how that happened; I mean I didn't touch the settings of my camera, bur for sure must have touched the settings and didn't notice that and totally not remember! 
The internet is  like a box of miracles and so I found a tool to convert the TIF files into JPG files and now I can luckily show this one here.
Of course I've reset the settings in my camera.