iPhone does not show transparent GFX generated with copyChannel

I have just verified a problem with an iPhone: I have tested the project with iPad mini too, and surprisingly it can’t even start the application, when the iPhone 5 loads it, even if with a graphic glitch. Browser is Safari.

The problem is this:

  • when I play animations coming from a simple spritesheet (with or without alpha) I see the animation correctly
  • when I play animations coming from a combination of a spritesheet + an alpha channel image, made adding the alpha image to the spritesheet with copyChannel, animations play but they are invisible.

Is this a known Safari incompatibility? Someone here told me that copyChannel can be unpredictable in certain environments.