Pulsing Alpha Channel
Everything can be controlled by a changing limit.

The (2 * limit - 1) results in either 1 for limit 1 or -1 for limit 0 controlling whether you are increasing or decreasing.

color.a * sign >= limit if limit = 1 and color.a > 1 or limit = 0 and color.a &lt; 0

and maxAlpha - limit is either 1 if limit is 0 or 0 if limit is 1

Remove

private float minAlpha = 0.0f;

private bool alphaIncreasing = false;


Add

private float limit = 0.0f;


New Update code.

void Update()
{
    var color = image.color;
    float alphaChange = Time.deltaTime / time / 2.0f;
    var sign = 2 * limit - 1;
    color.a += sign * alphaChange;
    if (color.a * sign &gt;= limit)
    {
        color.a = limit;
        limit = maxAlpha - limit;
    }
    image.color = color;
}