Formatly

Resize Images

Change image dimensions with live width/height controls, an aspect-ratio lock, and one-click presets for social media. Everything is processed in your browser — nothing is uploaded.

Image resizer

Drop images here

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JPG · PNG · WebP · up to 100 MB per file

Drop files to begin — the resizer will appear here.

    How it works

    Fit, Fill, or Stretch — pick your strategy

    Every resize is a trade-off between keeping the whole picture and hitting exact dimensions. Fit scales the image so it sits entirely inside your target box — nothing is cropped and nothing is distorted, but the output may be smaller than the box on one side (a 3:2 photo fitted into a square leaves empty space conceptually; here the canvas simply becomes the fitted size). Fill scales until the box is completely covered and then center-crops the overflow, guaranteeing exact dimensions — the right choice for cover photos, avatars, and square social posts. Stretch forces the exact size regardless of proportions, which visibly distorts anything that is not already the same shape. The preview canvas always shows the true output, so what you see is what you download.

    Choosing dimensions

    Type any width and height, or use a preset: Instagram feed posts at 1080×1080, Stories and Reels at 1080×1920, YouTube thumbnails at 1280×720, X headers at 1500×500, and favicons at 64×64. With the aspect-ratio lock on, editing one dimension updates the other automatically to avoid accidental distortion. Two practical notes: shrinking an image is always safe (it often looks sharper), while enlarging cannot invent detail and gets softer the further you push it. And for screen use, only pixel dimensions matter — "DPI" is ignored by browsers and social apps, so do not chase it.

    Batch processing and export

    Add as many images as you like: the first (or whichever you click) becomes the focused file with the live preview, while the same dimensions, mode, format, and quality apply to every file in the batch. Each row shows original vs. output dimensions and file size with its own download button, and "Download all as ZIP" bundles the set. Output names include the new dimensions (e.g. photo_1080x1080.jpg) so batches stay organized. As with every Formatly tool, all of this runs locally — your images never leave your device.

    Frequently asked questions

    What is the difference between Fit, Fill, and Stretch?

    Fit scales the image down (or up) so the whole picture fits inside your target width and height without changing its proportions — no cropping, no distortion. Fill scales so the target box is completely covered and then center-crops the overflow, giving you exact dimensions (great for cover photos and square posts). Stretch forces the image to the exact dimensions, which distorts anything that is not already the same aspect ratio. When in doubt, use Fit.

    Will resizing reduce image quality?

    Downscaling (making an image smaller) is safe and often makes photos look sharper. Upscaling (making it larger) cannot invent detail, so results look progressively softer the further you go — doubling is usually acceptable, quadrupling rarely is. Exporting at a high quality setting (90+) preserves the most detail in the resized result.

    What size should I use for social media?

    The preset buttons cover the most common ones: Instagram feed posts are 1080×1080, Instagram Stories and Reels are 1080×1920, YouTube thumbnails are 1280×720, and X (Twitter) headers are 1500×500. Use Fill mode with these presets to get the exact required dimensions, cropping included.

    Does resizing change the file format?

    Only if you ask it to. "Keep original format" preserves the input type (JPG stays JPG, PNG stays PNG). You can also convert on export — for example, resize a PNG screenshot and export it as a much smaller JPEG or WebP in one step.

    Are my images uploaded to a server?

    No. Resizing, preview rendering, and ZIP building all happen locally in your browser. Your images never leave your device, there is no queue or account, and the tool works offline once the page has loaded.