How to set image on Texture

Hi All, i am new bee in Unity 3d and i want to do just little task is that i want to set image onto “Texture”, i don’t know method that how can i set image onto texture on runtime, and how can i set its transparency low please help me, i don’t need Texture2D i just need Texture and this is my requirement and image is in .PNG format.
I also want set image from documents directory onto this texture.
Thanks in Advance this will be great for me.

Edited

// Image is saved in Document directory…
string fileName = Application.persistentDataPath + “/myMarkerImage.jgp”;
//to check whether file exist or not…
if (File.Exists(fileName)){
// myTexture Connect with image texture from Inspector…
myTexture.name = fileName;
// rendering or showing texture onto view…
renderer.material.mainTexture = myTexture;
}

It appears you are trying to load a texture at runtime from Application.persistentDataPath and apply it to a material. For loading an image, the WWW class is a good bet:

Texture LoadImage(string file) {
	string fileName = Application.persistentDataPath + "/"+file;
	if (File.Exists(fileName)) { // myTexture Connect with image texture from Inspector.....
		fileName = "file://"+fileName;
	
		WWW www = new WWW(fileName);
		while (!www.isDone);
		return www.texture;
	}
	return null;
}

Note you can get rid of your file check (File.Exists) and use the www.error instead. In addition the use of ‘while(!www.isDone)’ will ‘hang’ your app until the file load is complete (success or failure), so I’d only do it for local files, and probably not for huge files. For internet loads or large loads, I recommend you use www in the traditional way in a Coroutine and using a ‘yield’.