YouTube is experimenting with a significant change to its mobile app that could transform how users browse videos on their phones. The platform is currently testing dynamic thumbnail and video sizes on the Home feed, moving away from the familiar uniform grid layout that has defined the experience for years.
According to details shared by YouTube, the test automatically adjusts the size of videos and thumbnails as users scroll. Some entries will take up more vertical space to create a more immersive feel, while others fit into tighter slots. This aims to help individual videos stand out better on limited mobile screens and encourage more engagement as people browse.
The experiment is rolling out to a limited group of users on both Android and iOS. Not everyone will see the change immediately, as is typical with YouTube’s A/B testing approach. If you’re part of the test group, you may notice varied thumbnail heights and some images appearing cropped to fit the new layouts.
Importantly, creators have nothing to worry about regarding their original uploads. YouTube has confirmed it is not editing, compressing, or permanently altering any thumbnail files. The resizing happens only on the viewer side during this test to gather data on how different presentations affect viewer behavior and click-through rates.
This mobile update follows a similar experiment with larger thumbnails on the desktop version earlier in 2025. YouTube’s stated goal is to refine the Home feed to boost overall engagement and improve the viewing experience on smartphones, where most users discover content.
While the test is still in its early stages, it reflects YouTube’s ongoing efforts to evolve its interface amid competition from short-form video platforms and changing user habits. There is currently no opt-out option for users who encounter the new layout, but such experiments typically conclude after sufficient data is collected.
Many users have mixed feelings about frequent YouTube UI changes, but this one focuses squarely on making the endless scroll more visually dynamic. Keep an eye on your app updates—your Home feed could look noticeably different soon.
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