Correct color from picture without lightings?

I try to make 2D jump and run game and I got a intense color pictures for a block that the character will jump over. I dont know how to do it at all so I just put directional light at 0 degree (facing directly to the object) so I can see the color of the mesh. However I noticed the object became too bright and flashy losing its original color and when I reduce the intensity of the light things doesnt go better, basically I cant get the original color of the picture. You can see original picture in the content below and the result in the scene.