I have added the following rewrite rule to my .htaccess (above the previous rewrite rule): RewriteRule ^wp-content/uploads/(.*)$ dl-file.php?file=$1 [QSA,L]
You presumably have another .htaccess file in the /wp subdirectory that contains the main WordPress directives (ie. # BEGIN WordPress etc.).
You should be adding the above rule to the /wp/.htaccess file, not the one in the root.
When accessing a URL of the form /wp/... the mod_rewrite directives in the root .htaccess file are completely overridden by the mod_rewrite directives in /wp/.htaccess (by default). The mod_rewrite directives in the root .htaccess file are not even processed, since mod_rewrite directives are not inherited by default.
The dl-file.php script should then be in the root of the WordPress installation, not in the document root.
Aside:
However, since I installed WordPress in a subdirectory, the image path actually is
.../wp/wp-contents/uploads/image.jpg.
Although this would imply you have a mismatch of URLs… some containing the /wp subdirectory and some (your static assets) not.
The first rule you posted rewrites requests to the /wp subdirectory for any request where it is omitted. (The .htaccess file in the /wp subdirectory ensures it does not rewrite requests that already contain /wp.)
You should either:
-
Include
/wpin all your URLs -
Omit
/wpfrom all your URLs.
You currently appear to have a mixture of both.