Base64 to texture decoding, js -> webgl

I'm building webgl application in unity and I want to allow user to import image (png).
Javascript: function process(input) { let file = input.files[0]; let reader = new FileReader(); reader.onload = function (e) { unityInstance.SendMessage('Phone', 'SetImageFromBase64', e.target.result); }; reader.readAsDataURL(file); } C#: private void Awake() { SetImageFromBase64(); } public void SetImageFromBase64(string str = "data:image/png;base64,iVBORw0KGg(...)") { var bytes = Convert.FromBase64String(str.Substring("data:image/png;base64,".Length)); var tex = new Texture2D(2, 2); tex.LoadImage(bytes); tex.wrapMode = TextureWrapMode.Clamp; tex.Apply(); meshRenderer.material.SetTexture(MainTex, tex); } And when application is started, image is properly loaded, but when I try to load same image using javascript all I'm getting is black texture. Do anyone have an idea why this is happening?