Cover and Thumbnail Size for Reels and Shorts
Enter your cover image's size, format and file size to see whether YouTube and Instagram accept it.
Short answer: A YouTube Shorts thumbnail should be 9:16 (2160 x 3840 (9:16) recommended), at least 640 px tall, JPG or PNG, up to 2 MB on mobile or 50 MB on a computer. An Instagram Reel cover is a JPEG up to 8 MB in sRGB, 9:16 recommended; any other ratio is cropped to the middle 9:16 rectangle. A YouTube video thumbnail should be 16:9 and at least 640 px wide.
Last verified against each platform’s own documentation; sources are listed below.
Cover and thumbnail requirements
| Image | Format | Size | Dimensions | Notes |
|---|---|---|---|---|
| YouTube Shorts thumbnail | JPG or PNG | 2 MB on mobile, 50 MB on desktop | Height at least 640 px; 2160 x 3840 (9:16) | Custom Shorts thumbnails can only be added in YouTube Studio on a computer, and the account must be verified. |
| YouTube video thumbnail | JPG or PNG | 2 MB on mobile, 50 MB on desktop | Width at least 640 px; 3840 x 2160 (16:9) | A regular (landscape) video. |
| Instagram Reel cover | JPG | 8 MB | 9:16 recommended | sRGB colour space. If the image is not 9:16 Instagram uses the middle 9:16 rectangle as the cover. |
| TikTok cover | A frame of the video | Not stated | The video’s own dimensions | Through the TikTok posting API the cover is a frame of the video (video_cover_timestamp_ms); the first frame is used if none is set. No separate cover image upload is documented there. |
Sources
- YouTube Help: Add video thumbnails
- Instagram Platform: IG User Media (Reels specifications)
- TikTok for Developers: Direct Post API reference
This reference as plain text: /tools/cover-thumbnail-size.md
Frequently asked questions
What size is a YouTube Shorts thumbnail?
YouTube Help recommends 2160 x 3840 (9:16) for Shorts, with a minimum height of 640 pixels. File size is capped at 2 MB on mobile or 50 MB on a computer, in common types such as JPG or PNG.
Can I add a custom thumbnail to a YouTube Short?
YouTube Help says custom Shorts thumbnails can currently only be added in YouTube Studio on a computer, and that the account must be verified.
What size is an Instagram Reel cover?
Meta's publishing reference asks for a JPEG up to 8 MB in sRGB and recommends 9:16 to avoid cropping or blank space. If the image is not 9:16, Instagram uses the middle-most 9:16 rectangle.
Can I set a custom cover for TikTok through a scheduler?
Through the TikTok posting API the cover is a frame of the video (video_cover_timestamp_ms); the first frame is used if none is set. No separate cover image upload is documented there.
Does SchedulePost upload a custom cover?
This page documents what each platform accepts. Check the SchedulePost composer for the cover options it offers; the tool does not assume them.