Thumbium
Thumbium is a web tool that generates thumbnails from text prompts for YouTube and Shorts.
What Thumbium is
Thumbium is a web tool that generates thumbnails from text prompts for YouTube and Shorts. Projects support 16:9 widescreen YouTube layouts and 9:16 vertical Shorts layouts. Users can choose image types such as Photoreal, Cartoon, Anime, or 3D, or leave the choice on Auto. Subject, product, and background photos can be added to guide a scene. Each request can produce up to four variations, and plain-language instructions can be used to edit an existing thumbnail. Thumbium uses the user’s own OpenAI API key, while image-generation charges are paid separately to OpenAI: the listed costs are $0.04 per thumbnail at Medium quality and $0.16 at High quality. One-time packages are Hobby at 17.00 USD, Business at 29.00 USD, and Agency at 49.00 USD, each shown as 50% off normal pricing. The current double-credit special provides 100, 200, or 500 monthly thumbnails respectively. Gallery items are deleted after 30 days.
Good
- Supports YouTube and Shorts formats
- Multiple selectable image styles
- Up to four variations per request
- Plain-language thumbnail editing
- Optional reference photos
Watch out
- No free plan or trial
- Requires your own OpenAI API key
- OpenAI charges are separate
- Gallery deletes thumbnails after 30 days
Who it suits
Thumbium suits YouTube and Shorts creators who need prompt-based thumbnails, variations, and text-described edits. The listed packages identify Hobby, Business, and Agency audiences by publishing volume.
Verdict
Thumbium provides prompt-based thumbnail creation with format controls, reference images, and editable variations. Account for separate OpenAI usage costs and the package’s monthly generation limits.
Plans and prices
From Thumbium's own pricing page, checked 8 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Hobby | $17, paid once | 100 thumbnails every month in the current double-credit special · YouTube and Shorts · uses your OpenAI key · One time; $17 shown as 50% off the normal $34 price |
| Business | $29, paid once | 200 thumbnails every month in the current double-credit special · YouTube and Shorts · uses your OpenAI key · One time; $29 shown as 50% off the normal $58 price |
| Agency | $49, paid once | 500 thumbnails every month in the current double-credit special · YouTube and Shorts · uses your OpenAI key · One time; $49 shown as 50% off the normal $98 price |
The facts
Each one read from Thumbium's own pages, with the date it was checked.
What it does
- Editing
- Users can describe changes in plain language and ask the AI to edit an existing thumbnail.checked 8 Oct 2026
- Formats
- Projects can use widescreen 16:9 YouTube or vertical 9:16 Shorts sizing.checked 8 Oct 2026
- Gallery retention
- Generated thumbnails remain in the gallery for 30 days and are then deleted automatically.checked 8 Oct 2026
- Integration
- Thumbium uses the user's own OpenAI API key, and image-generation charges are paid to OpenAI.checked 8 Oct 2026
- Monthly limits
- Generation pauses when the package's monthly thumbnail limit is reached and resumes at the start of the next month unless another package is added.checked 8 Oct 2026
- Purpose
- Thumbium generates thumbnails from a text prompt for YouTube and Shorts.checked 8 Oct 2026
- Refund policy
- The pricing page offers a 14-day money-back guarantee; its refund policy says OpenAI usage charges are separate and not refundable by Thumbium.checked 8 Oct 2026
- Styles
- Users can choose art styles and image types such as Photoreal, Cartoon, Anime, and 3D, or leave the image type on Auto.checked 8 Oct 2026
- Support
- The site lists support at [email protected].checked 8 Oct 2026
- Variations
- Thumbium can generate up to four thumbnail variations per request.checked 8 Oct 2026
- Who it is for
- The page describes Hobby for creators posting a few videos monthly, Business for regular uploaders, and Agency for agencies and high-volume channels.checked 8 Oct 2026
Money
- Generation costs
- The page lists OpenAI costs of $0.04 per thumbnail at Medium quality and $0.16 at High quality.checked 8 Oct 2026
Where it runs
- Reference photos
- Users can optionally add subject, product, and background photos for the generated scene.checked 8 Oct 2026
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