How can I ignore file_upload validation.

[eluser]jedre[/eluser]
Hello again!

I have form to edit article. On the form I have text, textarea and file field.
So when I edit article and I want change only Title field, file field is empty.
When I send a form I get message error like this: You did not select a file to upload.

How can I skip file_upload validation when I edit article and I won't change file?

Of course, I want have possibility edit file by this form, but not always when I edit article.

Sorry for my English.

[eluser]xwero[/eluser]
Before the file upload you write

Code:

if($_FILES['userfile']['error'] == 4)
{
   // no file added
}
else
{
   // do upload
}