-+ t r & f \.(bmp|BMP|gif|GIF|jpg|JPG|jpeg|JPEG|png|PNG|xpm)$ | t t
-= t r & f \.(bmp|BMP|gif|GIF|jpg|JPG|jpeg|JPEG|png|PNG|xpm)$
++ t r & f \.(bmp|BMP|gif|GIF|jpg|JPG|jpeg|JPEG|pbm|PBM|ppm|PPM|png|PNG|xbm|xpm)$ | t t
+= t r & f \.(bmp|BMP|gif|GIF|jpg|JPG|jpeg|JPEG|pbm|PBM|ppm|PPM|png|PNG|xbm|xpm)$