I would add a mutator attribute for the image, in which you can manage the image, and store it's path. Something like this:
// in your Post model
public function setImageAttribute( $file )
{
if ($file)
{
// perform the store here
// save the file path to the database field
$this->attributes['image'] = $fileNameToStore;
}
}
Then you can use just this:
Post::create([
'title' => request('title'),
'description' => request('description'),
'prize' => request('prize'),
'location' => request('location'),
'image' => request('image')
]);