[From disk]
http://answers.unity3d.com/questions/432655/loading-texture-file-from-pngjpg-file-on-disk.html
[From web]
http://docs.unity3d.com/ScriptReference/WWW.LoadImageIntoTexture.html
[Loading into Texture2D]
http://docs.unity3d.com/ScriptReference/Texture2D.LoadImage.html
[Creating material at runtime]
http://answers.unity3d.com/questions/921203/building-a-unity-5-standard-material-at-runtime.html