[lacatoire]

In the three-argument form, imagepolygon(), imageopenpolygon() and imagefilledpolygon() derive the point count from $points, but the "too few points" error blamed argument 3, which is the colour there. It now blames $points in that form, and argument 3 is kept for the deprecated $num_points form.

To reproduce

<?php
imageopenpolygon(imagecreatetruecolor(20, 20), [1, 1, 2, 2], 0xffffff);

Before: ValueError: imageopenpolygon(): Argument #3 ($num_points_or_color) must be greater than or equal to 3

After: ValueError: imageopenpolygon(): Argument #2 ($points) must have at least 3 points