.htaccess MIME types

I have a folder (photos) with .jpg files without the extension.
For example, " 20100914165406970 " is a name of a unique file inside /photos.

How should I make it force as jpg image file?
Is it possible to do with .htaccess?
Adding or forcing image/jpeg mime to such files?

For example, if someone views http://server/photos/20100914165406970, it should serve the image (it is a real file being accessed). It should not show the download-popup window.
It should behave as if I am browsing http://server/photos/20100914165406970.jpg

Any .htaccess tricks to put inside /photos/.htaccess?


The easiest way is to instruct Apache to serve the extensionless files IN THE photos DIRECTORY AS JPG IMAGES. Because I always have a problem getting my head around the AddType directive when NO file extension is used, though, I’d redirect extensionless files to the .jpg version with:

# .htaccess in the photos subdirectory

RewriteEngine on
RewriteRule ^([0-9]{17})$ $1.jpg [L]

Of course, that REQUIRES the seventeen digits shown in your example so you may have to change the number of digits specified to suit your requirements.