Thumbnail Generator — Free & Instant

Yes. Drop a .heic file from your iPhone directly onto the tool. It is automatically converted to a compatible format in your browser before being resized to each selected size. No app or software needed.

Yes, it works on modern Android and iOS browsers. On iPhone, you can pick photos from your camera roll when you tap the upload area. The layout adapts to smaller screens.

No hard limit is enforced — processing happens in your browser, so the limit is your device memory. In practice, even large 20–30 MB files from a DSLR or iPhone work fine on most devices.

JPG works everywhere and gives the smallest file sizes for photos, making it ideal for social media uploads. PNG is lossless and best for graphics, logos, and images with text. WebP is the most efficient for web use but some platforms may not accept it — use JPG for social media to be safe.

No. All processing happens entirely in your browser using the Canvas API. Your images are never sent to any server. Once you close the tab, all image data is cleared from memory.

Each run generates one source image at multiple sizes. If you need to resize many different images, repeat the process for each one — upload, select platforms, download ZIP. For true batch processing across many source files, that is a planned enhancement.

The most clicked YouTube thumbnails share a few consistent traits: a clear, high-contrast subject (usually a face with an expressive reaction), bold readable text in 2–3 words that creates curiosity or promises a benefit, and a colour scheme that stands out in a grid of other videos. Avoid cluttered compositions — thumbnails are shown as small as 120×67 px on mobile, so anything small disappears. Use a consistent style across your channel so returning viewers recognise your thumbnails instantly. The 1280×720 px preset in this tool gives you the full resolution YouTube recommends.

Twitter/X displays profile photos at 400×400 px (1:1 square, cropped to a circle in the UI). The header/banner image displays at 1500×500 px (3:1 ratio). Keep important content — your logo, face, or text — centred and away from the top-left corner, where the profile photo overlaps the banner on desktop. This tool generates a 1500×500 header preset under the Twitter/X card option. Export as JPG for the smallest file size that Twitter will accept without recompression.

Facebook personal profiles display cover photos at 820×312 px on desktop and 640×360 px on mobile. For Facebook Pages (business pages), the cover photo is the same size but the safe zone for text and logos is slightly different — keep key content within the centre 820×250 px to avoid it being cropped on mobile. Profile photos on both personal and page profiles should be 170×170 px minimum. The OG / Blog Image preset (1200×630) also works for Facebook link previews when your content is shared.

Open this page in Chrome or Safari on your phone. Tap the upload area and pick an image from your Gallery or Photos app. Select the YouTube preset (1280×720), choose Cover mode so the image fills the frame edge-to-edge, and tap Generate. Download the thumbnail directly — no app needed. For best results, use a portrait-oriented photo of a face or a clearly readable text graphic as the source image. If you are shooting specifically for a thumbnail, bright, even lighting and a plain or blurred background give the best outcome.

Shopify recommends product images at 2048×2048 px (1:1 square) for the highest quality across all themes. Minimum acceptable size is 800×800 px. Shopify automatically generates smaller thumbnails from your uploaded image, so always upload the largest version you have. For collection page banners, 1200×400 to 1600×500 px works well at a 3:1 ratio. Use the "By Pixels" mode in the Resize Image tool to hit 2048×2048, then upload to Shopify — the platform handles all other sizes from there.