ExtrudeImage.cs

using UnityEditor;

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEditor.VersionControl;

public static class MeshSaverEditor {

    [MenuItem("Assets/Extrude Image")]
    public static void ExtrudeImage () {
        var tex = Selection.activeObject as Texture2D;
        var sprite = Sprite.Create(
            tex, 
            new Rect(0.0f, 0.0f, tex.width, tex.height), 
            new Vector2(0.5f, 0.5f), 
            100.0f, 
            0,
            SpriteMeshType.Tight
        );
        var vertices = sprite.vertices;
        var tris = sprite.triangles;
        var uv = sprite.uv;
        var go = new GameObject(tex.name);
        var mf = go.AddComponent<MeshFilter>();
        var mr = go.AddComponent<MeshRenderer>();
        var mesh = new Mesh();
        mesh.name = tex.name;
        mesh.vertices = vertices.Select(x => (Vector3)x).ToArray();
        mesh.uv = uv;
        mesh.triangles = tris.Select(x => (int)x).ToArray();
        var shader = Shader.Find("Standard");
        var material = new Material(shader);
        material.name = tex.name;
        material.mainTexture = tex;
        mr.material = material;
        mesh.RecalculateBounds();
        mesh.RecalculateNormals();
        mesh.RecalculateTangents();
        mf.sharedMesh = mesh;
    }
    
    [MenuItem("Assets/Extrude Image", true)]
    static bool ValidateExtrudeImage (MenuCommand menuCommand)
    {
        var path = AssetDatabase.GetAssetPath(Selection.activeObject);
        return path.Contains(".png");
    }

}