I agree with him. The technique by which you enlarge an image will affect how the aliasing will look. With the right plugin, you could even make the jaggies disappear entirely by enlarging the image with a fractal algorithm.
Doing a bilinear or bicubic resample will blur the enlarged image and make the jaggies look smoother and better than they actually are. You should to an integer pixel resize, a.k.a. "nearest neighbour" in photoshop. You need to be careful with this too, though. You must resize to an exact multiple of original image proportions e.g. 2x the size, 3x the size, 4x the size etc. If you do a nearest neighbour resize to something like 1.5x the original image size, then every other pixel will be twice as big as its neighbour. This would make the jaggies look worse than they actually are.
I've also seen that photoshop 6 (dunno about later versions) is crap for enlarging images in this way, even with "nearest neighbour" resizing to exactly twice the original image size, it skips lines and adds others. This is why I only use Paintshop Pro when individual pixels matter.
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