This will not do what you want.
suppose you want to upload the file foo and the file already exists. Your code would check for foo0, which propably does not exist, and overwrite foo.

Besides, you append th number, giving you: foo0,foo01,foo012,....
And to concatenate strings you should use ".".

One way to do it:

$num="";
while(-e "$Data/$category/$imagename$num"){
  $num++;
}
$imagename = $imagename.$num;
[download]

---- amphiplex