Short answer: remove similar photos by choosing the keeper first, then deleting the weaker versions around it. The mistake people make is treating similar-photo cleanup like duplicate cleanup, even though similar shots still need judgment.
This is why similar-photo cleanup gets slow manually. The challenge is not finding exact waste. The challenge is protecting the best expression, sharpest frame, or strongest composition while still reducing the clutter around it.
How to choose the keeper first
Pick the sharpest or best-timed image before looking at the rest as deletion candidates.
Favor the photo with the best expression, composition, or clearest subject.
Treat uncertain groups as second-pass decisions instead of forcing them immediately.
What similar-photo cleanup is really removing
Burst leftovers and near-duplicate frames.
Several attempts at the same moment where only one or two photos are strong.
Repeated compositions that create decision clutter more than exact duplicate waste.
Why this is different from duplicate cleanup
Duplicate cleanup removes exact copies. Similar-photo cleanup removes the weaker alternatives around one good keeper. That difference is what makes grouped side-by-side review so important.
If you want the feature page next, open similar photos. If you want the concept explanation first, continue to Duplicate vs Similar Photos.
The safest similar-photo cleanup rule is simple: choose what deserves to stay before deciding what can go.