Image thumbnails under the product gallery: +6.06% conversion
Test run byDave DiederenSyntra Labs
Commentary byLiftArchiveOur analysis, not theirsShowing image thumbnails under the product gallery lifted conversion rate by 6.06% and revenue per visitor by 7.34%. Dave Diederen ran this A/B test on a Shopify store with 162,815 visitors and 2,469 orders. The test was still running when results were shared.
- Conversion rate rose 6.06%, from 1.47% to 1.56%, with a 93% probability of beating control.
- Revenue per visitor rose 7.34%, from $1.49 to $1.60, estimated at about $49,045 a month.
- Profit per visitor rose 7.56%, from $1.06 to $1.14.
- Average order value was roughly flat, up 1.20% from $101.44 to $102.66.
- The ranges were wide (conversion -2% to +15%), so a small negative effect was not ruled out.
The change
A row of thumbnails replaces the slider dots under the main image.
Simplified mockup drawn by LiftArchive from the shared screenshots.
Control
The gallery was a swipeable slider with dots underneath. Shoppers could see the next image peeking in from the side but had no preview of the full set.
Variant
The main image got arrow buttons, and a row of six small thumbnails sat beneath it. Shoppers could see every image at a glance and jump to any of them.
Why it likely won
Our reading of the result, not the practitioner's claim.
- thumbnails show how many images exist, so shoppers look at more angles before deciding.
- seeing the product from several sides reduces doubt about what will arrive.
- dots on a slider hide content, while thumbnails make it visible without effort.
Caveats: The test had no end date when shared and the probability to win was 93%, short of the 95% many teams use. Results come from a single store.
Who ran it
Dave Diederen (@DaveDiederen) shared this test on X. The numbers and screenshots are theirs.
View the original post on X
How to run this test on your store
- Hypothesis
- If we show a row of image thumbnails under the main product image, then more visitors will buy, because they can see the whole image set and check the product from every angle without guessing.
- Primary metric
- Conversion rate
- Guardrails
- Revenue per visitor
- Page load time on mobile
- Return rate
- Who should test it
- Stores with several good product photos per item, especially visual products or ones with colour options. It will add little if you only have one or two images or if extra images slow the page.
Questions
Do product image thumbnails increase conversions?
In this test, adding thumbnails under the gallery raised conversion rate by 6.06% and revenue per visitor by 7.34%. The probability of beating control was 93%.
Are thumbnails better than slider dots on mobile?
Here the control used a swipeable slider with dots, and the thumbnail version did better. Thumbnails show what each image is, while dots only show how many there are.
Do thumbnails affect average order value?
Not much in this test. AOV moved only 1.20%, so the gain came mainly from more people buying.
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