UNIX pipes

why does this work: firefox yotsuba.jpg
but not this: ls|grep yotsuba|firefox

note: ls|grep yotsuba produces: yotsuba.jpg

what am I doing wrong?

text file = ASCII, UNICODE ect
binary file = all others

its to do with the phasing of the information. text files can be loaded moar effectually if they are read in byte by byte (ASCII this means charater by charater). This is true in all OSs, including windows.