Not necessarily, as we canonically draw a distinction between garters and garter belt. The difference between suspenders and garters comes in what's being held up-- pants/skirt or leggings/stockings? Were it not the tiniest bit ambiguous what's exactly being held up, I wouldn't have even asked. I assume it's the thighhighs that are attached to her shirt here because of the position, size of clasp, and colour; but as anime had thrown us a number of curveballs in the past, I thought I would attempt to verify.
PS: In the metadata, there's distinction between stockings and thighhighs. Make note of it, yes?
