TextureFormat.ASTC_RGB_8x8 quality is slightly reduced.

[Thura122016]

Bug
When I edit TextureFormat.ASTC_RGB_8x8, It changes the TextureFormat.ETC2_RGBA8 and the image quality is slightly reduced.
Can you fix it or How can I?

[K0lb3]

All texture compression algorithms employed by Unity are lossy.
When replacing a texture, it either has to be stored as uncompressed type or has to be compressed again.
Uncompressed increases the size of the asset by a lot (2~8x of the original image data size), while recompression creates a loss in quality.

You can set an uncompressed target texture type by using Texture2D.set_image. You can achieve no compression by using TextureFormat.RGBA32.