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A good cover decides whether people tap. Crealix generates one for every video when it finishes generating — made from your video’s hero moment, a 2–4 word hook and your visual style — and places it on the first frame of the exported MP4, so TikTok, Reels and Shorts use it as the thumbnail. Open Thumbnail in the tool rail to change it. The panel has two halves: AI cover at the top and manual design below.
The Thumbnail Editor with AI cover options

① Current cover · ② AI modes · ③ Optional direction · ④ Generate · ⑤ Pick a headline

Designing a cover by hand

① Cover frame · ② Upload / Library · ③ Title text · ④ Style presets · ⑤ Position · ⑥ Size, rotation and colors

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AI cover

Pick a mode (②), optionally describe what the cover should show (③), and click Generate with AI (④). The new cover replaces the current one (①).
The cover’s text is kept inside the area platforms don’t cover with buttons and captions, for 9:16, 16:9 and 1:1. Short, high-contrast hooks (2–4 words) work best — like “NO MIRES LA VENTANA” above.

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Design it by hand

Prefer full control? Scroll down the panel:
1

Choose the background

Cover frame (①) lists a frame from every scene — click one to use it. Or Upload your own image, or pick one from your Library (②).
2

Write the headline

Type it in Title text (③) and choose a font.
3

Pick a style preset

(④) Impact, TikTok, Highlight, Neon, Gradient, Outline, News or Clean. Each preset sets colors, background and effects in one click.
4

Place and fine-tune it

Snap position (⑤) to Top, Center or Bottom, or drag the text directly on the preview. Then adjust font size, rotation, text color, text shadow and text background (⑥). Reset starts over.
Save the project and the cover is used on your next render.

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YouTube thumbnails

When you publish to YouTube, Crealix also uploads your cover as the video’s custom thumbnail. For 16:9 videos, design the cover at 16:9 so it matches what viewers see in search and suggested videos.
YouTube only accepts custom thumbnails from verified channels. If your channel isn’t verified, the video still publishes but YouTube picks its own thumbnail. Verify your channel at youtube.com/verify — it takes a minute with a phone number.