[grab] Fix "wrong" header info ...

... it's not exactly wrong, but from a strict point of view only "image/jpeg" is correct, while "image/jpg" isn't.

While most browser handle this nicely anyways, there are browsers that don't, e.g. Dolphin.

plugin/controllers/models/grab.py

@@ -54,7 +54,7 @@ def __init__(self, request, session):
 			sref = 'screenshot'
 		request.notifyFinish().addErrback(self.requestAborted)
 		request.setHeader('Content-Disposition', 'inline; filename=%s.%s;' % (sref, fileformat))
-		request.setHeader('Content-Type','image/%s' % fileformat)
+		request.setHeader('Content-Type','image/%s' % fileformat.replace("jpg","jpeg"))
 		request.setHeader('Cache-Control','no-cache')
 
 	def requestAborted(self, err):