iOS Email Image Caching During the course of developing email campaigns I use my own iPhone as one of many testing devices.  The problem is, if I modify an image, I must modify the name of the file and the link to it in the code as well because my iOS device will incessantly reload the cached image from the previous test if I try use the same file name.

Is there any way to turn this caching off so that the images are downloaded each and every time?  I can't even seem to find a way to purge the cache.
If you force quit Mail (double-tap the home button, swipe the app up) the embedded image cache seems to be cleared when you relaunch it.