Self-taught PHP has a small problem to ask Master

test.php
echo filesize ("http://localhost:81/qq.jpg/");
echo filesize ("e:/apache/htdocs/qq.jpg/");
?>
This filesize function why so love newspaper warning,
Warning:filesize () [Function.filesize]: Stat failed for e:/apache/htdocs/qq.jpg/in E:\Apache\htdocs\test.php on line 4

Apache Path no problem, it's wrong.

Reply to discussion (solution)

God, don't laugh at me, rookie.

FileSize ("e:/apache/htdocs/qq.jpg/");
What does the last '/' mean?

I read in Baidu said sometimes less this also will be reported warning

