diff --git a/doc/pbr_to_standard.png.meta b/doc/pbr_to_standard.png.meta
new file mode 100644
index 0000000..97234a3
--- /dev/null
+++ b/doc/pbr_to_standard.png.meta
@@ -0,0 +1,68 @@
+fileFormatVersion: 2
+guid: 300c7a0839ab0e24bb25c7f268696f2e
+timeCreated: 1537519011
+licenseType: Free
+TextureImporter:
+  fileIDToRecycleName: {}
+  serializedVersion: 4
+  mipmaps:
+    mipMapMode: 0
+    enableMipMap: 1
+    sRGBTexture: 1
+    linearTexture: 0
+    fadeOut: 0
+    borderMipMap: 0
+    mipMapFadeDistanceStart: 1
+    mipMapFadeDistanceEnd: 3
+  bumpmap:
+    convertToNormalMap: 0
+    externalNormalMap: 0
+    heightScale: 0.25
+    normalMapFilter: 0
+  isReadable: 0
+  grayScaleToAlpha: 0
+  generateCubemap: 6
+  cubemapConvolution: 0
+  seamlessCubemap: 0
+  textureFormat: 1
+  maxTextureSize: 2048
+  textureSettings:
+    filterMode: -1
+    aniso: -1
+    mipBias: -1
+    wrapMode: -1
+  nPOTScale: 1
+  lightmap: 0
+  compressionQuality: 50
+  spriteMode: 0
+  spriteExtrude: 1
+  spriteMeshType: 1
+  alignment: 0
+  spritePivot: {x: 0.5, y: 0.5}
+  spriteBorder: {x: 0, y: 0, z: 0, w: 0}
+  spritePixelsToUnits: 100
+  alphaUsage: 1
+  alphaIsTransparency: 0
+  spriteTessellationDetail: -1
+  textureType: 0
+  textureShape: 1
+  maxTextureSizeSet: 0
+  compressionQualitySet: 0
+  textureFormatSet: 0
+  platformSettings:
+  - buildTarget: DefaultTexturePlatform
+    maxTextureSize: 2048
+    textureFormat: -1
+    textureCompression: 1
+    compressionQuality: 50
+    crunchedCompression: 0
+    allowsAlphaSplitting: 0
+    overridden: 0
+  spriteSheet:
+    serializedVersion: 2
+    sprites: []
+    outline: []
+  spritePackingTag: 
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: