"download blob image (stored in the database) to my computer" Code Answer

everything you output to the page is considered a file contents. i suppose you don't want "<br>" to be in the contents of your file.

second point - do not do any output before setting headers.

third point - exit('string') outputs 'string', so you output content of your file twice: with echo and with exit.

so, your code should look like:

$id=$_get["id"];
$sql = "select * from table1 where id=$id "; // 1
$res = $con->query($sql);
while($row = $res->fetch_assoc())
{ 
    $name = $row['name'];
    $size =  $row['size'];
    $type = $row['extension'];
    $image = $row['image'];
}

header("content-type: ".$type);
header('content-disposition: attachment; filename="'.$name.'"');
header("content-transfer-encoding: binary"); 
header('expires: 0');
header('pragma: no-cache');
header("content-length: ".$size);

echo $image;
exit();

By Shayan Pourvatan on June 29 2022