Knitwear disappoints people more than any other category, and the reason is physical rather than technical. A jumper is identified by its surface, and a screenshot is a format that throws surfaces away.
Why does a coat search better than a jumper?
Because a coat is identified by edges and a jumper is identified by texture.
Everything that separates one coat from another sits on its outline: the length, the closure, the lapel shape, the collar, the pocket placement. Those are hard boundaries between light and dark, and image compression preserves hard boundaries because they are what the eye notices.
Everything that separates one jumper from another sits on its surface: the stitch pattern, the gauge, the way the fabric catches light. Those are low-contrast detail spread over a large area, and compression discards low-contrast detail first, because discarding it is what makes the file smaller without the picture looking obviously wrong.
The result is that a cable knit and a plain jumper in the same colour converge as compression increases. Past a certain point they produce the same description, and Snagfit reads what survives rather than what was there. That is the same mechanism behind why the same photo gives different results, applied to one garment category where it bites hardest.
What is gauge, and why does it change the search?
Gauge is how fine or chunky the knit is, counted as stitches per inch.
A fine gauge merino jumper and a chunky hand-knit wool jumper can be the same colour, the same neckline and the same shape, and they are two entirely different products. They are made differently, priced differently, sold in different parts of a shop, and worn in different weather.
Shopping listings distinguish them clearly, with words like fine knit, midweight, chunky, bulky and hand knit. So a photo that shows the stitch size at all pushes the search into the correct half of the category, and a photo that does not leaves it searching both.
Gauge is easier to preserve than stitch pattern, because a chunky knit has larger features and larger features survive compression better. That is a small mercy: you are more likely to keep the difference between chunky and fine than the difference between cable and rib.
Which stitches are worth naming?
A short list covers most of what you will see.
Cable is the rope-like twisted column, usually running vertically. It is the most recognisable knit pattern and the one most often lost to compression, because its detail is in the twist.
Ribbed is vertical raised lines, evenly spaced. Fine rib and wide rib are different looks and both are common.
Waffle is a square grid of raised squares, sometimes called thermal.
Fisherman or aran combines cables with textured panels, traditionally in cream, and is a named category in its own right.
Jacquard or fair isle is a colour pattern knitted into the fabric rather than printed on it. This one survives compression better than the others, because it is a colour change rather than a relief.
Jersey or stockinette is the smooth flat knit that most basic jumpers and all t-shirts use.
Naming the stitch narrows a search further than almost any other single word, so when the photo carries it, the result improves a long way.
How do you keep the texture in the photo?
Two things, and the second one matters more than people expect.
Get closer. A jumper occupying the middle third of a full-length shot loses its stitch to downscaling before anything else happens. Crop to the torso.
Find side light. Texture reads through shadow. A knit lit flat from the front has no shadow in its stitches, so it photographs smooth no matter how chunky it is. The same knit lit from one side casts a small shadow into every stitch, and the pattern appears.
If you are choosing between frames in a video, take the one where the person is turned partly away from the main light. If you are photographing something you own, put it near a window and stand so the window is to one side rather than behind you.
This is the opposite of the usual advice about lighting, which is to get an even frontal light for accurate colour. For knitwear you are trading a little colour accuracy for the texture, and the texture is worth more here. The general rules are in why lighting changes what a search finds, and this is the one category where the exception applies.
Why is the neckline the field to rely on?
Because it is an outline, and outlines survive.
Crew neck, V neck, turtleneck, mock neck, funnel neck, boat neck, scoop and cowl are eight distinct search terms, and every retailer files knitwear under them. A neckline is a high-contrast shape at the top of the garment, right where the light usually is, and it stays readable in a compressed image long after the stitch has gone.
That makes it the reliable field on a bad photo. When a search comes back too wide, the neckline is often what you can add by hand to narrow it, because you can see it in the picture even when the description did not pick it up.
The same applies to sleeve treatment and hem. A ribbed cuff, a raw hem, a split side, a cropped length: all edges, all likely to survive. There is more on how these read in the guide on necklines and collars and the one on knitwear specifically.
Can a photo tell you what a jumper is made of?
It can tell you what the material looks like, which is a different thing.
Wool, cashmere, cotton and acrylic look similar in a photograph, especially at distance and especially after compression. The differences are real but subtle: cashmere has a soft surface halo and falls closer to the body, wool holds more structure, cotton has a flatter surface and a heavier drape, acrylic reflects light in a harder way and keeps its shape stiffly.
At screenshot resolution most of that disappears. Which means a jumper search can come back with results spanning a wide price range for what looks like one garment, and the thing separating them is the composition on the listing.
That is a fact about knitwear rather than a flaw in the search. Two jumpers can be visually near-identical and materially different, and the difference is in how they wear over two years rather than how they photograph today. The guide on what a garment is made of covers how to read a composition label, and it is worth reading before you buy anything knitted at the cheaper end.
What is the right crop for knitwear?
Torso, shoulder to hem, and no tighter.
You need enough of the garment to show its shape. A cropped boxy jumper and a long fitted one are different products, and the shoulder seam position tells you whether it is a drop shoulder, which sits down the arm, or a set-in one, which sits at the shoulder point. Both of those are visible only if the shoulders are in the frame.
Cropping right down to a patch of fabric gives you excellent texture and no shape at all. The description that comes out of it is a material and a colour with nothing to attach them to, and the search returns everything made of that material in that colour.
So: shoulders at the top, hem at the bottom, arms included if the sleeves have any detail. Everything below the hem and outside the arms can go. Cropping for a better match has the general version of this, and knitwear is the category where the balance between texture and shape is hardest to strike.
What should you do when the result is a wall of plain jumpers?
That is the classic knitwear failure, and it means the texture did not survive.
Try a different frame first. If the source is a video, there is often a moment where the person moves into better light or turns, and that frame may carry the stitch when the one you took did not.
If there is only one photo, add what you can see to the search by hand. You know it is a cable knit even if the description did not say so, and typing that word into a retailer's own search alongside the colour and the neckline usually gets you closer than another upload will.
And check the price range of what came back. If the results span a very wide range for the same-looking garment, the description was almost certainly generic, which confirms the texture was lost. What to do when you cannot find the exact item covers the rest of the fallbacks in the order worth trying them.