The tag is warranted, since Ryuuko in a wedding dress is a reference to
spoilerRagyou brainwashing Ryuuko with, e.g., "marrying" her to the Life Fibers/spoiler

The only things similar is that it is a shoulderless dress and has a veil. Besides the obvious color difference, this design is more open in the front, the veil lacks the tiara like part, there are no bridal gauntlets, there isn't a necklace, and this one has a choker.

I don't think this image carries any kind of spoiler.
I don't see how this image alone tells any event in the series.

Spoiler

Already, you wrote a spoiler, instead of the image.

The draw is an idea of this series, but not so representative to reveal the ending or another relevant moment of Kill la Kill.

PD: It's Ryuuko in a beautiful wedding dress.