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?

>>16
Learn what binary means. Learn to tell when people are misusing it. Unix people misuse it in two different ways: to speak of files with characters not usually found in text, and to speak of executable files.