NotebookLM reportedly testing custom banners beyond limited emoji labels

Andrew Romero | Feb 24 2026 - 8:42 am PT

On the back of expansive recent updates, NotebookLM appears to be testing the option to add banner images for further customization.

According to a recent post on Twitter/X by @testingcatalog, Google is reportedly testing a new function in NotebookLM that lets users add custom images to their notebooks. The image doesn’t present a lot of detail, and it’s hard to see what’s actually changed. A closer look reveals what looks like a “customize” option near the top of the chat window.

Google may soon allow users to customize their notebooks on NotebookLM with a banner image.

Do you have a notebook worth featuring? 👀 pic.twitter.com/5O1l4Xg8jx
— TestingCatalog News 🗞 (@testingcatalog) February 22, 2026

It’s unclear how the function will work. That is, whether NotebookLM users can add custom image banners or if the button lets Gemini 3.1 and Nano Banana generate something based on the context of that particular notebook. The source either hadn’t used the feature or it isn’t working just yet. Considering it seems to be a backend test, there’s a non-zero chance the feature hasn’t been sufficiently fleshed out.

It could work like other Google products, with a customization option that lets users pick a theme color or a gallery image. That wouldn’t leverage what NotebookLM offers users in terms of experience, though. It’s more likely that image generation will be utilized in some regard. The button does carry an image generation icon, which might hint at the latter.

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Conjecture aside, it looks like a nice way to differentiate notebook entries. The current system designates emojis for each notebook. It offers some visual breakup, but the options are limited in scope. Custom images would go a long way to bring some life to the experience.

This comes as NotebookLM recently underwent some major upgrades in the public version. That includes Gemini 3.1 Pro, added for better reasoning across varying topics one would embark on in the note-taking tool. Google also added a new slide deck revision feature so users can edit the generated presentations, with more control over the information presented.

The recently spotted banner feature in NotebookLM may not become available for a while, if ever. Still, it’s interesting to see the concept of more customization options being added as the tool becomes more capable.