Etiquette
Video submissions
Some judges take short video material and some do not; ask before sending, keep it short, and expect it to be treated as more to review than a photo set.
Guides on Etiquette: Being declined, Nothing exotic, Opening well
You can send a video instead of photos only if the judge agrees first: photos are the default material for a commission, and video is a variation some judges accept and some do not. Ask first, and do not attach one before you know the answer.
Why the default is photos
A short set of clear photos is the fastest thing for a judge to review, quote against, and respond to specifically. How many photos to send, and which already covers why a small, clear set beats a folder; video adds a further layer on top of that, because a clip is longer to watch, harder to reference precisely, and not every judge has built video review into their process at all.
Some do, and for certain requests it is genuinely the better material - a brief about movement, presence, or something a still photo cannot show is one a short video answers more honestly than a photo set trying to stand in for it. That is exactly why it is worth asking rather than assuming either way.
Ask, then wait
A one-line question - "would you take a short video instead of photos for this?" - is the whole of the etiquette, and it belongs before any material is attached, not alongside it. Sending material before a judge has agreed to look is a consent breach in miniature with photos, and the same logic applies with more weight to video, which is a larger and more identifying piece of material to have sent unsolicited. Wait for a yes before attaching anything.
Keep it short if the answer is yes
If a judge agrees to take video, treat that agreement as permission for something brief, not an open door. A few seconds to a short clip covers what a judge needs to assess; a long recording is closer to raising the scope of the whole request than to a swap of format, and it should be flagged as such rather than sent and left for the judge to discover.
What video adds to privacy
UK data protection law already treats this kind of material with care: the ICO lists data concerning a person's sex life among the special categories of personal data that carry extra protection. Video material identifies a person more readily than a carefully chosen still photo does, simply because there is more of it: movement, background, longer duration, more chances for something incidental to appear in frame. Anything sent for review should be treated as material to be careful with regardless of format, but the same carelessness matters more in a clip than in a photo, and it is worth checking a recording for the same things you would check a photo for before sending it - what is visible around the edges, what a background reveals, whether anything identifying made it into frame without you noticing while filming. What happens to material after a judge has reviewed it is worth reading regardless of format, and it applies with extra weight once the material is a recording rather than a still.
Expect it to be reviewed as more, not the same
A judge who agrees to video material is typically going to treat it as a heavier submission than a photo set, and that can reasonably show up in the quote. Judges do not price by the photo because photo count barely changes the labour; video is different, because reviewing footage properly takes real time in a way that flicking through five stills does not. Asking the format question early, before the brief is finalised, means this gets folded into one quote rather than surfacing as a surprise after the fact.
None of this has a parallel on the automated side of the market. A scoring model is built to process a still image, not footage, so video is not a format choice there at all - it is simply outside what the tool does. If a still photo genuinely will not show what you are trying to convey, a proper measurement taken by a documented method is sometimes the more precise answer than either photo or video, and an automated score works from one clear image every time, which is worth knowing if simplicity matters more to you than which format the assessment arrives in. For the broader question of which route to take at all, Rate Cock's direct comparison is the place to start.