Yep!

```
fs.js:113
    throw new Error('Unknown encoding: ' + encoding);
          ^
Error: Unknown encoding: image/jpeg
    at assertEncoding (fs.js:113:11)
    at Object.fs.writeFile (fs.js:939:3)
    at Object.LocalFileStore.write (/Users/jon/Dropbox/Sites/butter/lib/file-store.js:84:6)
    at /Users/jon/Dropbox/Sites/butter/server.js:170:19
    at fs.js:266:14
    at Object.oncomplete (fs.js:107:15)
```