When someone copy paste a photo url on my site they can open it i a webrowser without being logged in to the site. Is there a way to prevent this?

below is my htcaccess file...   i did a lot of searching but i cant find it

thanks

Options +FollowSymLinksRewriteEngine On
AddEncoding gzip .gzAddEncoding gzip .gzip<FilesMatch "\.(js.gz|js.gzip)$">  ForceType text/javascript</FilesMatch><FilesMatch "\.(css.gz|css.gzip)$">  ForceType text/css</FilesMatch>
AddOutputFilterByType DEFLATE text/plainAddOutputFilterByType DEFLATE text/htmlAddOutputFilterByType DEFLATE text/xmlAddOutputFilterByType DEFLATE text/cssAddOutputFilterByType DEFLATE application/xmlAddOutputFilterByType DEFLATE application/xhtml+xmlAddOutputFilterByType DEFLATE application/rss+xmlAddOutputFilterByType DEFLATE application/javascriptAddOutputFilterByType DEFLATE application/x-javascript
RewriteCond %{REQUEST_URI} !/sitemap.xmlRewriteCond %{REQUEST_URI} !/robots.txt
RewriteCond %{REQUEST_URI} !^/index\.phpRewriteCond %{REQUEST_URI} !/ow_updates/index\.phpRewriteCond %{REQUEST_URI} !/ow_updates/RewriteCond %{REQUEST_URI} !/ow_cron/run\.phpRewriteCond %{REQUEST_URI} !/e500\.php#RewriteCond %{REQUEST_URI} (/|\.php|\.html|\.htm|\.xml|\.feed|robots\.txt|\.raw|/[^.]*)$  [NC]RewriteCond %{REQUEST_FILENAME} (/|\.php|\.html|\.htm|\.xml|\.feed|robots\.txt|\.raw|/[^.]*)$  [NC]RewriteRule (.*) index.php