Htaccess show no_found picture if picture is not exist

RewriteEngine On
RewriteCond %{REQUEST_URI} \.(jpg|jpeg|gif|png)$ [NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule .*$ /no_picture.png [L]

Let's break it down as to what each line means.

RewriteCond %{REQUEST_URI} \.(jpg|jpeg|gif|png)$ [NC]

Check to see if the requested file is of a file extension in the parentheses (). In this case, we're testing to see if the file name ends in either .jpg, .jpeg, .gif or .png

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d

Check that the file is not there and it's also not a directory.

RewriteRule .*$ /no_picture.png [L]

If a requested resource/file passes all those tests, then it's an image that does not exist. So serve back the image of no_picture.png to the browser. This will keep the filename. If you want to redirect to the no_picture.png filename, change [L] to [R]

auto refresh for every 5 mins in Javascript

We can do this function with just html  or just javascript

Refresh document every 300 seconds using HTML Meta tag add this inside the head tag of the page

 <meta http-equiv="refresh" content="300">

Or using Java Script:

            setInterval(function() {
                  window.location.reload();
                }, 300000);