Plugin : http://dl.dropbox.com/u/1412774/InjectImage/pode_injectImage.0.2.zip
.capx : http://dl.dropbox.com/u/1412774/InjectImage/InjectImage.0.2.capx
Edit : added this info : you can also directly inject the URL of an image, instead of a base64 string !
Since you can extract current Image (http://www.scirra.com/forum/behavior-extract-sprite-to-base64-string_topic50577.html), why not inject Image ?
For the moment, you can inject base64 string, and it's going to replace the current Sprite image's texture.
.capx : http://dl.dropbox.com/u/1412774/InjectImage/InjectImage.capx
Plugin : http://dl.dropbox.com/u/1412774/InjectImage/pode_injectImage.0.1.zip
BEWARE !! The collision polygon used is stilll the one from the first Sprite ! So for the moment, if you use collisions, and want that everything goes smooth, keep injecting images of roughly the same shape !
If you don't use collisions, you don't care about that anyway
I'm going to provide a way to specify a new polygon in a new release...