You can't set multiple HTTP headers in one call. Once a certain content-type is set in the HTTP header, you're stuck with it. You can however generate different data & content-types depending on certain parameters... check Re: Displaying randomly created png's in HTML for more specifics and a link to the correct RFC.
Greetz
Beatnik
... Quidquid perl dictum sit, altum viditur.
These are two separate web server requests. The first one fetches the html document with the IMG SRC=/cgi-bin/images/whatever.png. This content type should be set to text/html.
The web browser will make a separate request for whatever.png. This will be a separate cgi script that just sets the content type to image/png (i think) and basically prints the binary image file.
"I have a script which needs to output both html and graphics on the same page. " and
"..., it appears I will need to send two content-type headers ( text/html and image/png )."
The question was kinda tricky. My response did include the two request solution.
I doubt Cines answer below actually works on web browsers. MIME types and HTTP content-types are similar but not exactly the same.
Greetz
Beatnik
... Quidquid perl dictum sit, altum viditur.