Thumb­nails – kleine Bilder mit großer Kraft

Similar to how a package image in retail can encourage a purchase, a thumbnail on the internet creates the first im­pres­sion of images, videos, or other web content. A well-crafted thumbnail image sparks curiosity and leads to more clicks.

What is a thumbnail?

A thumbnail is a smaller preview image designed to give a quick visual im­pres­sion of the content, whether it’s a video, image, or article. Thumbnail images are commonly used across the internet, including in online shops, where they help display multiple products in an organised way. Clicking on the thumbnail directs you to the original file or product page.

The biggest advantage of thumb­nails is the reduced file size. When a large number of image or video contents are initially loaded as small preview images, it no­tice­ably improves the website’s loading time. Users can then decide which content they want to view in full size. Ad­di­tion­al ad­vant­ages include:

• Space-saving: Thumb­nails provide a quick overview of many contents in a small area.
• User-friend­li­ness: The brain processes images faster than text, so thumbnail images support intuitive nav­ig­a­tion.
• In­ter­activ­ity: At­tract­ive preview images encourage users to click on content (click-through rate) and interact with the page.

Where are thumb­nails used?

Thumbnail images can be found all over the web—such as on YouTube, in Google Image Search, in social media feeds, or in online shops. However, their design and style vary sig­ni­fic­antly depending on the platform and purpose. While they primarily serve as neutral product images on Amazon, YouTube thumb­nails often resemble small ‘bill­boards’ that visually tease the content and capture attention.

YouTube thumb­nails

With the intense com­pet­i­tion on YouTube, it’s essential for the thumbnail to capture attention within seconds to improve key KPIs like the click-through rate (CTR). Many creators on the platform use emotional facial ex­pres­sions, graphic elements like arrows or circles, and strong contrasts to make their thumb­nails stand out from the crowd. Con­sist­ent branding is also key, achieved through uniform colours, a recurring layout, or featuring the same people.

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Thumb­nails in Google Image Search

To display a large number of results to users sim­ul­tan­eously, Google uses thumb­nails in its image search instead of high-res­ol­u­tion original images. These are linked preview images that belong to websites. If YouTube videos are also listed in the search results, Google uses the cor­res­pond­ing video thumbnail as a preview. Thumbnail images also play a central role in ‘Google Discover’ for the click prob­ab­il­ity of an article.

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Thumb­nails in online shopping

In online stores, preview images often display a neutral view of the product against a white back­ground (cutout), without elaborate staging. In fashion stores, models often appear in a neutral pose on thumb­nails; aes­thet­ic­ally pleasing per­spect­ives and detail shots are shown only on the product detail page.

Many stores now auto­mat­ic­ally provide more in­ter­activ­ity through modern shop systems. For example, when you hover over the thumbnail (mouseover), you can often browse through ad­di­tion­al views or display al­tern­at­ive colours without leaving the page. This makes product research sig­ni­fic­antly faster and more user-friendly.

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Common sizes for thumb­nails

Depending on the website, the purpose and therefore the optimal size of thumbnail images can vary. Here are common guidelines (as of 2025):

• Google Search / Discover: Google re­com­mends images that are at least 1,200 pixels wide for optimal display in Discover and Search. While smaller images (starting at 300 pixels) do work, larger images are often displayed more at­tract­ively (e.g., as a large card format).
• Amazon: Amazon requires a minimum width of 500 pixels on the longest side. However, it is re­com­men­ded to use 1,000 to 1,600 pixels on the longest side. This size activates the ‘zoom feature’ on the product page, which is crucial for con­ver­sions.
• YouTube: Thumb­nails on YouTube are displayed in a 16:9 format. The optimal size is 1,280 x 720 pixels (minimum width 640 pixels). File sizes should ideally remain under 2 MB.
• Pinterest: Pinterest is a vertical search engine. Ideal images have a 2:3 aspect ratio, such as 1,000 x 1,500 pixels. Deviating formats are often cropped or less favoured in the feed.

Legal situation for thumb­nails

In the UK, thumb­nails of copy­righted images fall under the Copyright, Designs and Patents Act 1988, which protects them similarly to full-size originals and requiring per­mis­sion or a valid exception to avoid in­fringe­ment claims. Unlike the US fair use doctrine, UK law offers narrower defenses such as fair dealing for criticism, review, or news reporting, but thumb­nails for general website or blog use (e.g., previews or dec­or­a­tion) typically do not qualify unless trans­form­at­ive and non-com­mer­cial. To minimise risks, use self-created images, public domain works, or Creative Commons-licensed content with at­tri­bu­tion, obtain explicit per­mis­sions, or embed via links to originals rather than hosting copies yourself.