NSR is an image format associated with NewsRoom, a desktop publishing software program designed for Atari home computers. This brand was particularly popular in the 1980, being one of the first types of computers to address nontechnical home users. Similar extensions include PH and BN. In case you found such a file, it is probably very old and it might not be possible to open it using regular image viewers.
JPEG JPG PNG GIF TIFF TIF BMP ICO EMF WMF AI PDF EPS PS EPI WEBP WEBPLL JP2 PCX TGA DWG DWF DXF DGN WMZ CGM DRW GBR PCT MIF PLT PCL SVG WPG CIN DCX DIS HRU MTV PRC RAD PIC RLA QRT SGI XBM XPM SWF CAL PSD JXR BPG APNG DDS SVGZ CG4 FLIF