TextAsset.bytes

public byte[] bytes ;

Description

The raw bytes of the text asset. (Read Only)

using UnityEngine;

public class Example : MonoBehaviour
{
    // Load a .jpg or .png file and then drag it on the imageTA variable.

    TextAsset imageTA;

    void Start()
    {
        var tex = new Texture2D(4, 4);
        tex.LoadImage(imageTA.bytes);
        GetComponent<Renderer>().material.mainTexture = tex;
    }
}