Summernote post or update a content with image in Laravel controller . Supports any utf content. Note:

summernote.php

public function domPost($content)
{
        libxml_use_internal_errors(true);
        $dom = new \DomDocument();
        $dom->loadHtml('<?xml encoding="utf-8" ?>'.$content);    // must include this to avoid font problem
        $images = $dom->getElementsByTagName('img');
        if(count($images)>0)
        {
            foreach($images as $k => $img)
            {
                $src = $img->getAttribute('src');
                # if the img source is 'data-url'
                if(preg_match('/data:image/', $src))
                {
                    # get the mimetype
                    preg_match('/data:image\/(?<mime>.*?)\;/', $src, $groups);
                    $mimetype = $groups['mime'];
                    # Generating a random filename
                    $filename = uniqid();
                    $filepath = "uploads/$filename.$mimetype";
                    // if you use intervention image package
                    $image = Image::make($src)
                            ->encode($mimetype, 100)  # encode file to the specified mimetype
                            ->save(public_path($filepath));
                    // if you use intervention package end
                    // if you not use intervention package start
                    $destinationPath = public_path().'/uploads/';
                    $filename = $file->getClientOriginalName();
                    $src->move($destinationPath, $filename);
                    // if you not use intervention package end    
                    $new_src = asset($filepath);
                    $img->removeAttribute('src');
                    $img->setAttribute('src', $new_src);
                }
            }
        }
        # modified entity ready to store in database
        $content = $dom->saveHTML($dom->documentElement);

        return $content;

    }