I am currently in development of Unity game on Android. I've run to an issue with performance on some of the old Android phones and decided to compress all images to ETC1 Format. However, every time I select ETC the preview shows DTX5 or DTX1! Why is that happening!?
All other compressions shows normally in the preview except ETC1! In the end I have tried overriding for Android, forcing the texture to be to the power of 2 in Photoshop but nothing helps! Is this normal behavior? I don't really think so, if all other compression formats show in the preview.
Here's a screenshot of the issue.
I just made a few tests in my project and it seems you can't select ETC1 unless your project's target platform is set to Android in the build settings. When i had it set to standalone i could select all formats, but the preview shows DXT1 for most mobile formats (ETC1 / PVRTC / ATC). Once i switched the platform to Android all assets were reimported and the preview showed the correct format.
So make sure you have selected Android as target platform in your build settings. You have to click "switch platform" to apply this setting.
Another issue could be that your source image has an alpha channel. ETC1 doesn't support an alpha channel. Try saving your image without an alpha channel. If you need alpha you can't use ETC1.