Why do browsers inefficiently make 2 requests here?

Question

I noticed something odd regarding ajax and image loading. Suppose you have an image on the page, and ajax requests the same image - one would guess that ajax requests would hit

Answer 1

This may be a shot in the dark, but here's what I think is happening.

According to, http://api.jquery.com/jQuery.get/

dataType
  Type: String
  The type of data expected from the server. 
  Default: Intelligent Guess (xml, json, script, or html).

Gives you 4 possible return types. There is no datatype of image/gif being returned. Thus, the browser doesn't test it's cache for the src document as it is being delivered a a different mime type.