Allow hotlinking but redirect when I am my own referrer!

Question

I want to, using htaccess, allow hotlinking BUT if someone views an image on my site I want to redirect them to a "hosted" version of the image where I display my navigation etc.

So essentially anyone hotlinking from an external site will not be affected but if someone views the image on my server directly i.e. www.domain.com/image.jpg itll redirect. I also want to make sure I can display images correctly from within my site too.

Can anyone help?

EDIT: Here is the code I currently have

RewriteCond %{REQUEST_FILENAME} \.jpg$
RewriteCond %{HTTP_REFERER} =""
RewriteRule ^userpics/covers/(.*).jpg$ /view/$1.html [R=301]

RewriteRule ^view/(.*).html$ /view.html?img=$1 [L]

Thanks

Answer 1

Use .htaccess

RewriteEngine on
RewriteCond %{REQUEST_URI} \.(jpg|png|gif)$
RewriteCond %{HTTP_REFERER} ^https?://yoursite\.com/.*$ [NC]
RewriteRule ([^/]+)$ url_to_script?img=$1

You could simplify

RewriteCond %{HTTP_REFERER} ^https?://yoursite\.com/.*$ [NC]

to just

RewriteCond %{HTTP_REFERER} yoursite\.com [NC]

And the rule can be written as

 RewriteRule (.*) url_to_script?img=$1

if you need to include the path to the image in your parameter.

Answer 2

You should use mod_rewrite, if the HTTP_REFERRER is empty then redirect to /image-with-nav.php?image=$1
Try something like this
RewriteEngine on

RewriteCond %{HTTP_REFERER} ^$

.* image-with-nav.php?image=$1 [L]

Answer 3

Now, what you need to check is the referrer because the URL is always the URL of your image, since it is a http request. You could go with something like this:

RewriteCond %{REQUEST_FILENAME} \.(jpg|png|gif)$
RewriteCond %{HTTP_REFERER} =""
RewriteRule (.*) http://someurl.com [R=301]