If you directly link to a binary file, such that its URL starts:

/content/download/...

and you're using the passthrough handler, the HTTP response includes a "Content-disposition: attachment;..." header.

This is usually fine, unless you want to make things appear inline in the browser (e.g. PDFs).

My suggestion is to allow this to be controlled via an ini setting.

The attached patch allows you to set a MimeDisposition variable in the FileDisposition group of file.ini, and control which MIME types are sent inline.

eg.
file.ini.append.php:

[FileDisposition]
MimeDisposition[application/pdf]=inline

will send PDFs inline, but leave everything else alone.

hth
vittal