Can IMP show attachments or html inline?
IMP is capable of showing certain attachments inline (i.e., in the message body, rather than appearing in a new window on request), but in some cases it risks exposing the user to a security problem in the browser: by enabling inline HTML, any JavaScript (ActiveX, Java, etc.) in the attachment might be executed by the browser. We try to filter out any active content, but just like with any filter, it might not be perfect and let some code through. Enabling inline HTML attachments is discouraged.
Of course, this will only work for elements that could be part of a regular HTML page or that have a MIME viewer (attachment renderer) in Horde that converts the original attachment into HTML output.
Create the files horde/config/mime_drivers.local.php and horde/imp/config/mime_drivers.local.php (IMP 4: edit the files horde/config/mime_drivers.php and horde/imp/config/mime_drivers.php) to enable inline support for the mime types you wish to have displayed inline. Simply add an 'inline' setting (IMP 4: set the 'inline' array element) for that mime type to true to enable a type. As noted above, not all mime types can be shown inline; if there is no 'inline' array element for a mime type in mime_drivers.php than that type can not be viewed inline.
For example, to enable inline HTML support you would set:
1 $mime_drivers['imp']['html']['inline'] = true;