TextureImageImporter

TextureImageImporter.cs

using UnityEngine;
using UnityEditor;
using System.IO;

public class TextureImageImporter : AssetPostprocessor
{
    static readonly string[] targetExtensions = { ".tga" };

    void OnPreprocessTexture ()
    {
        bool isValidExtension = false;
        foreach (var extension in targetExtensions) {
            if (Path.GetExtension (assetPath).ToLower ().Equals (extension)) {
                isValidExtension = true;
                break;
            }
        }

        if (!isValidExtension) {
            return;
        }
           
        var importer = assetImporter as TextureImporter;
        importer.textureType = TextureImporterType.Advanced;
        importer.npotScale = TextureImporterNPOTScale.None;
        importer.alphaIsTransparency = true;
        importer.mipmapEnabled = false;
        importer.lightmap = false;
        importer.normalmap = false;
        importer.linearTexture = false;
        importer.wrapMode = TextureWrapMode.Repeat;
        importer.generateCubemap = TextureImporterGenerateCubemap.None;
    }
}