Thumbnail Sizes and Specs for Every Platform (YouTube, Shorts, TikTok, Reels)

The quick reference

Platform requirements change. The specs below reflect current platform recommendations as of this article's publish date — verify current requirements on each platform's official help documentation before making final decisions.

Now the detail.

YouTube thumbnail specifications

Recommended size: 1280 × 720 pixels

YouTube's documentation recommends 1280×720 as the standard custom thumbnail size. This is a 16:9 aspect ratio, which matches YouTube's default video player ratio. At this size, thumbnails display correctly in the YouTube feed, in search results, in suggested video panels, and on embedded players.

The minimum accepted size is 640 × 360 pixels, but thumbnails at minimum size appear lower quality when displayed in high-resolution contexts. Always produce at 1280×720.

File size limit: 2 MB

A 1280×720 JPEG at moderate quality is typically well under 1 MB. PNG files are larger — a 1280×720 PNG can approach 2 MB if it contains complex image data. If you're exporting as PNG and approaching the 2 MB limit, export as JPEG at high (but not maximum) quality instead — the visual difference is negligible at thumbnail display sizes.

Accepted formats: JPG, PNG, GIF

JPEG is the most widely used format for thumbnails. It provides good quality at small file sizes. PNG is worth using when your thumbnail contains large areas of flat colour or text — PNG's lossless compression preserves sharp edges better than JPEG. Animated GIFs are accepted but do not animate in most thumbnail display contexts. Note: YouTube serves thumbnails to viewers as WebP, but the upload interface accepts JPG, PNG, and GIF — not WebP.

Channel verification requirement

Custom thumbnails require a verified YouTube channel (phone number verification or account in good standing above a threshold of subscribers — check YouTube's current requirements in the Help Centre as these thresholds can change).

The safe zone

YouTube's help documentation recommends keeping important content away from the edges of the thumbnail. The platform crops thumbnails in some contexts (particularly on mobile devices in portrait orientation), and important content near the edges can get cut off.

A common rule of thumb: keep faces, key visual elements, and text within the central 1100 × 620 area of a 1280×720 thumbnail (roughly a 50–60 pixel margin on each side). This ensures the most critical visual content survives cropping in all display contexts.

For text specifically, keeping text well within the safe zone also prevents it from being obscured by platform UI elements (like the video duration badge, which appears in the bottom-right corner of thumbnails).

YouTube Shorts cover image specifications

Shorts cover image behaviour is different from standard YouTube thumbnails and YouTube's documentation on this is less consistent than for standard videos. The Shorts format is primarily vertical (9:16), and custom cover image upload behaviour can differ between the mobile app and desktop YouTube Studio — and may change as the platform evolves.

Unlike standard YouTube thumbnails (where 1280×720 is clearly documented), the Shorts cover workflow varies by device and app version. Some creators use a vertical crop (9:16) of their image; others use a standard 16:9 thumbnail as the cover. The resizer preset for Shorts and TikTok in FatThumb's free tools uses 1080×1920 (9:16) — matching the vertical format the platform is built around.

For accurate current guidance on Shorts cover images, check YouTube's official Help Centre directly, as the recommended approach can change with app updates.

TikTok cover image specifications

Recommended size: 1080 × 1920 pixels (9:16 vertical)

TikTok is a mobile-first vertical platform. Its cover images are displayed at a 9:16 ratio matching the video format. A 1280×720 (16:9) image will be cropped when used as a TikTok cover.

If you're cross-posting from YouTube to TikTok, either:

1. Create a dedicated vertical crop of your thumbnail for TikTok, or
2. Compose your original thumbnail with the key content centred vertically so both the 16:9 and the centre-crop of 9:16 work

The practical approach for most creators is to use the 1280×720 image as-is for YouTube and then create a separate vertical cover for TikTok either by cropping or by generating a separate vertical-composition version.

TikTok's file size limits are not prominently documented in the same way as YouTube's — check the TikTok Creator Portal for current upload specifications.

Instagram Reels cover image specifications

Recommended size: 1080 × 1920 pixels (9:16 vertical)

Instagram Reels uses a 9:16 vertical format, and the cover image is displayed as a 4:5 crop of the Reel frame in the grid view. The full 9:16 image is shown in the Reel player view.

Instagram recommends a minimum size of 1080 × 1350 pixels (4:5) for content that needs to display correctly in the feed grid, but 1080×1920 (9:16) is the standard for Reels that will also be displayed in full-screen player view.

Safe zone for Instagram Reels: keep critical content away from the top and bottom of the 9:16 frame, as these areas are cropped or covered by UI elements in various display contexts. The most consistent display area is the central 1080 × 1350 region.

Working with a 1280×720 PNG across platforms

FatThumb outputs every generation as a 1280×720 PNG. Here's how that file works across each platform:

YouTube standard videos: upload directly. No processing needed.

YouTube Shorts cover: the workflow for Shorts cover images varies and is not as consistently documented as standard YouTube thumbnails — see the Shorts section above. For best results, use a vertical (9:16) crop or follow current YouTube Help Centre guidance.

TikTok: the 16:9 image will be letterboxed or cropped. For best results, crop to 9:16 before uploading as a TikTok cover, keeping your key subject centred.

Instagram Reels: same as TikTok — a 16:9 to 9:16 crop is needed for the full Reels view. For grid display, a 16:9 to 4:5 crop shows more of the image. Most creators crop to 9:16 for the full Reel view.

Format and quality recommendations

JPEG vs PNG: use PNG when your thumbnail contains significant text or areas of flat colour where sharp edges matter. Use JPEG for thumbnails that are primarily photographic images with smooth colour gradients. The visual difference at thumbnail display size is minimal, but PNG avoids the JPEG compression artefacts that can affect text legibility.

Resolution: always work at 1280×720 or above. Thumbnails upscaled from smaller sizes look blurry at display resolution — always start at the correct size or larger and scale down.

Colour space: use sRGB. YouTube and major platforms render in sRGB, and thumbnails created in wide-gamut colour spaces (like Adobe RGB or P3) may show colour shifts when displayed on standard screens.

Why getting specs right matters

The effort of producing a high-quality thumbnail is wasted if it's incorrectly sized, exported with quality loss, or displays incorrectly in the platform's UI. Getting specs right is a five-minute investment that protects the quality of every thumbnail you produce.

The 1280×720, 16:9, PNG or JPEG at under 2 MB specification for YouTube is straightforward to hit consistently — every AI thumbnail generator or design tool that outputs the correct size eliminates this as a variable entirely. Once you're in the habit of verifying the output file before uploading, thumbnail specs stop being something to think about and become one less thing to worry about.