How to Change Video Thumbnail

Customize your video's thumbnail to make it more appealing and engaging for viewers. A compelling thumbnail can significantly increase click-through rates and viewer engagement. Every video's thumbnail is managed on the Thumbnails tab of that video's page in the dashboard.

Before You Start

• The video must be uploaded. A frame captured during processing only exists once processing has produced one.
• Your account permission must include Manage Videos — both the upload and the frame-selection endpoints require that claim.
• Have your replacement image ready as a PNG or JPEG file of 5 MB or less.

Opening the Thumbnails Tab

1. In the dashboard sidebar, open Video Library (/projects).
2. Open the project that holds the video, then open the video itself. The video page is /videos/<VIDEO_ID>.
3. Select the Thumbnails tab.

The tab shows the Current Thumbnail (with an Active badge) when one is set, an Upload Custom Thumbnail card, and an Available Thumbnails grid of the frames captured from the video during processing.

Thumbnail Options

DynTube provides two ways to set your video thumbnail:

• Captured frames: during processing DynTube captures frames from the video and lists them under Available Thumbnails, ready to select
• Custom Upload: upload your own image from the Upload Custom Thumbnail card

Uploading a Custom Thumbnail

1. On the Thumbnails tab, find the Upload Custom Thumbnail card.
2. Use Select Image to choose a PNG or JPEG file of 5 MB or less. A larger file is refused before it is sent, with the message "Image size must be less than 5MB."
3. Check the Preview that appears under the picker.
4. Click "Upload & Use This Thumbnail". On success the tab reports "Thumbnail uploaded successfully" and the new image becomes the Current Thumbnail.

Choosing a Captured Frame

1. Scroll to Available Thumbnails.
2. Hover a frame — "Click to Use" appears over any frame that is not already active.
3. Click it. The tab reports "Thumbnail updated" and the frame is marked with a tick; the Current Thumbnail card refreshes to match.

If the grid instead reads "No auto-generated thumbnails available yet" with the helper "Thumbnails are generated during video processing.", the video has not yet produced any frames. Wait for processing to finish and reopen the tab, or upload a custom image in the meantime — the upload path does not depend on captured frames.

What Happens to an Uploaded Image

An uploaded thumbnail is not stored as-is. DynTube derives five sizes from it — xs (270 px tall), sm (360 px), md (1280×720), lg (1920×1080) and xl (2560×1440) — and stores each one so a surface can request the size it needs. Three details follow from that, and they are the reason for the size recommendation below:

• The md, lg and xl sizes are only stored when the source image is at least that large. A small upload is served from its smaller variants everywhere.
• Each size is produced by resizing to fixed dimensions rather than cropping, so an image that is not 16:9 is stretched to fit rather than trimmed.
• Every variant is re-encoded as JPEG unless the source was a GIF, so PNG transparency is not preserved.

Technical Requirements

Best Practices for Thumbnails

• Use High Resolution: Upload images at least 1280x720 pixels for crisp display
• Match 16:9: an image at another aspect ratio is stretched to fit, not cropped
• Keep It Relevant: Ensure the thumbnail accurately represents your video content
• Add Text Sparingly: If adding text, keep it large and readable
• Use Contrasting Colors: Make your thumbnail stand out in video listings, and keep the title overlay legible
• Keep essential content away from the corners, which surfaces may overlay
• Be Consistent: Maintain a consistent style across your video library for brand recognition

Related Articles

• How to Upload & Embed Videos
• How to Change the Video Player Skin
• Video Options FAQ