here is my html code form code.
<div class="form-group">
<label >Product Image</label>
<input type="file" class="form-control btn btn-primary" name="image[]" multiple="multiple">
</div>
you can use like this in your laravel controller file
in controller
$productSubImages = $request->file('sub_image');
foreach($productSubImages as $productSubImage){
$subImageName =$productSubImage->getClientOriginalName();
$subImageDirectory = 'product-sub-images/';
$productSubImage->move($subImageDirectory,$subImageName);
$subImageUrl =$subImageDirectory.$subImageName;
$subImage = new SubImage();
$subImage->product_id = $productId;
$subImage->sub_image = $subImageUrl;
$subImage->save();
}