About YouTube Thumbnail Resizer
YouTube recommends 1280×720 for thumbnails (16:9) and 1080×1920 for Shorts covers (9:16). The Resizer takes any source image and renders to either preset, with three fit options: cover (crop to fill), contain (pad with a solid colour), or blur fill (pad with a blurred copy of the image — popular for portrait sources on landscape thumbnails). JPEG quality is adjustable; everything happens in a 2D canvas with no upload.
- No uploads
- Browser-only
- Works offline
- 100% free
How it works
- 1
Drop your image
JPG, PNG, or WebP. Up to 50 MB — bigger inputs are slower but produce sharper output.
- 2
Pick the preset
Standard 1280×720 thumbnail or 1080×1920 Shorts cover.
- 3
Pick fit + quality
Cover for landscape sources, blur for portraits, contain when you want a solid background.
Related tools
Browse allGet the public thumbnail for any YouTube video — paste URL or ID.
Compose a 9:16 vertical cover with bold headline text.
Convert images to common social aspect ratios with crop, pad, or blur fill.
Per-platform compression presets for IG, YouTube, X, LinkedIn, WhatsApp.
Frequently asked questions
Are my files uploaded to a server?
No. Every tool on SnapToolz runs entirely inside your browser using JavaScript and WebAssembly. Your file is read locally, processed in memory, and the result is offered as a download. Nothing is sent to a server — there isn't one to send to.
Why JPEG and not PNG?
YouTube recompresses every thumbnail to JPEG anyway, so starting from PNG just means you upload a bigger file for no quality benefit. The output is JPEG at quality 85-95 depending on your selection.
What's the 'blur fill' mode?
When the source aspect doesn't match the target, the canvas needs filling. Blur fill renders the source image oversized and blurred behind a centred copy at correct aspect — the same trick TikTok and Reels use for vertical playback of horizontal video.
Does it work offline?
Yes. SnapToolz is a Progressive Web App. After your first visit, the app is cached on your device and every tool keeps working without an internet connection.
Is SnapToolz free?
Yes — every tool is 100% free with no sign-up, no watermark, no hidden tier. The whole platform is open source and we have no plan to gate features.