Create Unique Image Names

Question

What\'s a good way to create a unique name for an image that my user is uploading?

I don\'t want to have any duplicates so something like MD5($filename) isn\'t suita

Answer 1

How big is the probablity of two users uploading image with same name on same microsecond ?

try

    $currTime = microtime(true);
    $finalFileName = cleanTheInput($fileName)."_".$currTime;

// you can also append a _.rand(0,1000) in the end to have more foolproof name collision

    function cleanTheInput($input)
    {
     // do some formatting here ...
    }

This would also help you in tracking the upload time of the file for analysis. or may be sort the files,manage the files.