Image from ImageCache not responding to changes


In a plugin editor, I have a graphic resource I created via introjucer. It is an Image created from an imagecache:getfrommemory.

I'm trying to modify it in a timer callback, calling things like multiplyAllAlphas, destaurate, and I'm not seeing any effect.

I can confirm that my components like an imagebutton do respond in the same timer, using something like setAlpha. I have also confirmed that this image has an alpha channel.

What am I missing here? Why won't Images respond the same way as my ImageButtons?