New feature YouTube
YouTube thumbnails.set upload limit raised from 2MB to 50MB
What changed
The 14 September 2026 revision history entry raises the maximum upload size from 2MB to 50MB for thumbnails.set and playlistImages.insert. A 11 September 2026 entry also adds fhd, qhd and uhd thumbnail sizes for some videos. A separate effective date is Not stated.
What it means
Tools can upload higher quality custom thumbnails and playlist images without compressing them below 2MB.
Who is affected
Developers of tools that set YouTube thumbnails or playlist images, and marketers who use high resolution artwork.
What to do
Raise the file size check in your upload flow to 50MB for thumbnails.set and playlistImages.insert.
Primary sources
Checked against the source 26 Oct 2026
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