Unity IOS: Texture format?


Whenever i load a png via WWW class, XCODE says:

"WARNING: no native support for texture format 5, converting to 4!"

What exactly it does mean and what can i do about it?
I guess it takes a while for IOS to accomplsh it(?).
From what I understand IOS converts textures to its own format (PVRTC?).
I tried searching but I still dont know how to resolve the problem.
If I compress textures in inspector - it seems like those are only compressed in the inspector, cuz there is no real difference when it comes to loading a sprite via WWW class (real file is untouched?).

Did anyone had such warning?

Inspecting the enum TextureFormat, I found that 5 is ARGB32 and 4 is RGBA32.

When creating a new Texture2D from scripts, without a format specifier, Unity defaults to ARGB32, but is apparently not supported on iOS (tested on iPad 5).

Specifically using the constructor

newtex = newTexture2D (w, h, TextureFormat.RGBA32, false);

got rid of the problem on my iPad.

From what I’ve found out it seems that this error is about the texture size.
Namely: it have to be POT(Power Of Two) and Square, meaning, if you upload a sprite, its best to have a 128x128, 256x256 etc - just fill the unused pixels with alpha color.