4K YouTube Thumbnail Maker for Shorts, TikTok & Reels

A thumbnail is the first thing a viewer judges, and it is usually seen at the size of a postage stamp. Thumbnail Studio is SceneGen's thumbnail maker. It designs YouTube thumbnails and vertical covers for Shorts, TikTok and Reels, plus Instagram posts. It exports a 4K master for each one and checks how the design reads at phone size before you publish. This guide covers what it does, the sizes it uses and a step-by-step workflow.

What Thumbnail Studio is

Thumbnail Studio lives at /dashboard/thumbnails. A design is a stack of editable layers: a background, an optional cut-out subject, and text and shape layers (label boxes, arrows, circles). You can start from a finished SceneGen video, and then headline ideas come from its title and script and backgrounds can use its own frames. You can also start from a blank brief.

Each design comes with three variants, so you compare directions side by side instead of iterating on one idea. Designs cost no credits: rendering runs on SceneGen's own servers and AI backgrounds come from a free image service. The only limit is a daily volume cap, which is lower on the Free plan, because that capacity is shared with everyone's video renders.

Platform presets and export sizes

Layers are placed in relative coordinates, so the same design renders cleanly at every size. Each preset renders a large master first and then downsizes it for the platform's standard size. Text stays sharper that way than it would if you rendered small directly.

• YouTube thumbnail (16:9): 1280×720 standard, 3840×2160 (4K) master. YouTube's custom thumbnail help page now recommends 3840×2160 for videos and 2160×3840 for Shorts, and it still caps uploads from the mobile app at 2 MB. So the export includes the 4K master and a YouTube-ready JPEG under 2 MB that works from any device.
• Shorts / TikTok / Reels cover (9:16): 1080×1920 standard, 2160×3840 (4K) master.
• Instagram post 1:1: 1080×1080 standard, 2160×2160 hi-res.
• Instagram post 4:5: 1080×1350 standard, 2160×2700 hi-res.

If you work from a project, the studio suggests the preset that fits its aspect ratio: a 9:16 Short gets a vertical cover by default.

Safe zones, drawn per platform

Every platform puts its own interface on top of your image. The studio overlays those areas as warnings. On YouTube that means the video-length badge in the bottom-right corner, the hover icons in the top-right and the progress bar. On vertical covers it means the top tabs, the like/comment/share column, the caption area and the middle 3:4 crop that profile grids show. The zones are conservative approximations of the 2026 apps, so treat them as guidance, not rules.

The readability check (a heuristic, not a CTR prediction)

Most thumbnails are viewed at roughly 168×94 pixels, in search results on a phone or in "up next". The readability check renders your design at that size and measures:

• Text contrast between the headline's fill and whatever surrounds its letters at small size (the stroke, a label box, or the background behind it).
• Text size: the height of the capital letters at 168 px wide. Below about 7 px, text stops being readable.
• Length: more than five words is hard to take in at a glance.
• Subject size, when there is a cut-out subject.
• Safe zones: text or badges under the platform's UI.
• Clutter, focal point and colour: how busy the area behind the text is, whether the eye has one place to land, and how colourful the frame is. The check also compares the design with your own earlier thumbnails.

The result is a score out of 100 with the reasons behind it. It is a heuristic readability score, not a click-through prediction, and the studio labels it that way. What it catches is the common failure: a thumbnail that looks great on a 27-inch monitor and turns to mush in a phone feed. For what actually drives click-through rate, see thumbnail design for higher CTR.

Layouts, fonts and backgrounds

There are four layout templates: bold headline beside the subject, centred punch line with a label box, arrow + circle call-out, and a two-tone stacked headline. Highlight colours are picked to suit the emotion of the concept (shock, curiosity, surprise and so on).

The fonts are bundled display faces under the SIL Open Font License: Anton, Bebas Neue, Archivo Black, Bangers and Montserrat Black. When a headline uses a script those faces don't cover (Cyrillic in Bebas Neue, Arabic, CJK, Devanagari), the whole layer falls back to a font that covers it, because mixed fonts inside one headline look broken.

A background can come from three places:

• a free AI image, which takes about a minute each;
• a frame from your project, which is much faster;
• an upload of your own.

You can also upload a photo of yourself or a product. The studio cuts the subject out and adds a rim light.

How to make a 4K thumbnail, step by step

1. Open Thumbnail Studio and pick a preset (YouTube, vertical cover, or an Instagram size).
2. Optionally choose a finished project. You then get headline ideas from its script, and its frames become background options.
3. Type a headline of two to five big words, or leave it empty and let the studio suggest three.
4. Pick a background source (AI, project frame or upload) and, if you like, add a subject photo.
5. Generate. You get three variants, each with a preview and a readability score.
6. Open the best one in the editor. Fix whatever the check flags: raise contrast, enlarge the text, or move it out of a safe zone.
7. Export. You get the 4K (or hi-res) PNG and JPEG, a standard PNG and, for YouTube, a JPEG under 2 MB.
8. Choose Use as video thumbnail to attach it to the project. When SceneGen uploads the video to YouTube, it sets this thumbnail too.

When to use a layout match or a packaging pack instead

If you already have a thumbnail style you like, match a layout from a reference. If the video is finished and you want to test ideas, a packaging pack builds three title + thumbnail pairs for YouTube's Test & compare in one click.

Start designing

Open Thumbnail Studio, or create a free account first. The two free videos on the Free plan come with thumbnails, and every plan is on the pricing page.

Frequently asked questions

What size should a YouTube thumbnail be in 2026?

Use 16:9. YouTube's help page recommends 3840×2160 (minimum 640 px wide), and uploads from the mobile app are limited to 2 MB. Thumbnail Studio exports a 3840×2160 master plus a 1280×720 JPEG under 2 MB, which works from any device.

Can I make Shorts, TikTok and Reels covers too?

Yes. The vertical preset is 1080×1920 with a 2160×3840 master. It warns you about the like/comment buttons, the caption area and the 3:4 crop that profile grids show.

Does the readability score predict click-through rate?

No. It is a heuristic readability check (contrast, text size, word count, safe zones, clutter) measured at phone size. It is not a click-through prediction. Real CTR only comes from real viewers.

Do thumbnails cost credits?

No. Thumbnail designs cost no credits on any plan. There is a daily volume limit, lower on Free, because the free image service and the servers are shared.