wp upload bits doesn't work

hi
for a work i create my own page and create a form to send data to database (i create a table for my work in db)
and i need to upload an image to be shown in page
i search and find wp upload bits function
i crate a form and a file input like this:

<form action="#" method="post">
<input type="file" name="pic1" />
</form>

and with this function try to upload the image.
this function says:

$upload = wp_upload_bits($_FILES["pic1"]["name"], null, file_get_contents($_FILES["pic1"]["tmp_name"]));
foreach($upload as $ali){
echo $ali.'<br />';
}

but this function doesnt work and return an error:
name is empty
so i changed the code:

$upload = wp_upload_bits('ali', null, file_get_contents($_FILES["pic1"]["tmp_name"]));
foreach($upload as $ali){
echo $ali.'<br />';
}

but it doesn’t work again
and return an error (i think: the plugin is wasted)

it isn’t important for me to just use this function
i just want to upload an image to wp folders without any plugin

thank you all

[No bumping, thank you.]