| propertyName | プロパティーの名前 | 
テクスチャのプロパティー名から画像の大きさを取得します
Common texture names used by Unity's builtin shaders: 
"_MainTex" is the main diffuse texture. This can also be accessed via mainTextureScale property. 
"_BumpMap" is the normal map. 
"_Cube" is the reflection cubemap.
See Also: mainTextureScale property, SetTextureScale.