code: @Override
    public @NotNull ImageAssert isEqualTo(@Nullable BufferedImage expected) {
      return isEqualTo(expected, ZERO_THRESHOLD);
    }
docs: Verifies that the actual image is equal to the given one. Two images are equal if they have the same size and the
  pixels at the same coordinates have the same color.
  
  @param expected the given image to compare the actual image to.
  @return this assertion object.
  @throws AssertionError if the actual image is not equal to the given one.