code: @Override
    public @NotNull ImageAssert isNotEqualTo(@Nullable BufferedImage image) {
      if (areEqual(actual, image)) {
        failIfCustomMessageIsSet();
        throw failure(unexpectedEqual(actual, image));
      }
      if (image == null) {
        return this;
      }
      if (areEqual(sizeOf(actual), sizeOf(image)) && hasEqualColor(image)) {
        failIfCustomMessageIsSet();
        throw failure("images are equal");
      }
      return this;
    }
docs: Verifies that the actual image is not 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 image the given image to compare the actual image to.
  @return this assertion object.
  @throws AssertionError if the actual image is equal to the given one.