Data truncated when trying to save php image

I have a problem with saving a picture in the MySQL database with PHP in a blob field.

I received the following error message: "string data, right truncated: 1406 Too long data for column 'photo' on line 1"

I get the file like this:

$conteudo = file_get_contents($_FILES['imagem']['tmp_name']);

And the field where I'm trying to save this as blob.

Can anyone help me?