Image resizer

Exact pixel dimensions, a percentage, or a ready-made preset for Instagram, YouTube or a 2×2 inch print. All of it on your own device.

  • 0 uploads
  • No limits
  • No signup
  • Works offline

Pixels, percentages and presets

Three ways to say the same thing, useful in different situations.

Pixels are what forms, websites and specifications ask for. Type a width, leave the height empty, and the proportions are preserved automatically.

Percentage is for “make this smaller” without a specific destination — halving a folder of holiday photos before emailing them, for instance.

Presets cover the sizes people look up repeatedly:

Preset Pixels Used for
Instagram post 1080 × 1080 square feed posts
Instagram story 1080 × 1920 stories and reels
YouTube thumbnail 1280 × 720 video thumbnails (16:9)
LinkedIn banner 1584 × 396 profile cover image
X / Twitter header 1500 × 500 profile header
Facebook cover 820 × 312 page cover photo
2 × 2 inch @ 300 dpi 600 × 600 US passport and visa photos
35 × 45 mm @ 300 dpi 413 × 531 Schengen, UK and most Asian passports
A4 @ 300 dpi 2480 × 3508 full-page print

When the ratio does not match

If your photo is 4:3 and the target is 16:9, something has to give. There are only three honest options and the tool asks you to pick one:

  • Crop to fill keeps the target dimensions exactly and cuts the overflow from the edges, centred. This is what you want for thumbnails and banners.
  • Fit inside keeps the whole image visible and lands on the target’s longest edge, so one dimension comes out smaller than requested.
  • Stretch forces both dimensions and distorts the picture. It is included because occasionally it is genuinely what someone wants, but it will make faces look wrong.

For precise control over which part gets kept, use the cropper instead — it lets you pan and zoom inside the frame before committing.

Why Lanczos3

Downscaling is a resampling problem. Each output pixel has to represent an area of the source, and how you average that area determines how much detail survives.

Nearest-neighbour picks one source pixel and ignores the rest, which produces jagged edges and aliasing. Bilinear averages four, which is smoother but soft. Lanczos3 uses a windowed sinc function over a 6×6 neighbourhood, which keeps edges crisp without introducing the halos that oversharpening causes. It is slower — noticeably so on very large images — and it is worth it.

The implementation here is the same WebAssembly resizer that Squoosh uses, running in a Web Worker so a batch of fifty images does not freeze the page.

After resizing

Most people resizing for a form need to hit a byte budget too. The result screen offers a one-click hand-off to the compressor, and your resized file travels with it — no second download, no re-selecting files.

How it works

  1. 01Add your imagesDrop them on the page, click to browse, or paste from the clipboard.
  2. 02Choose how to size themType exact pixels, drag a percentage, or pick a preset. Leave the height empty to scale proportionally from the width.
  3. 03Decide what happens to the ratioWhen the target ratio differs from the source, choose to crop to fill, fit inside, or stretch.
  4. 04DownloadSave one file or the whole batch as a zip.

Questions people actually ask

Will resizing make the image blurry?
Downscaling done badly does. This resizer uses a Lanczos3 filter, which weighs a wide neighbourhood of source pixels for each output pixel and preserves detail far better than the nearest-neighbour or bilinear scaling most quick tools use. Upscaling is a different matter — no filter can invent detail that was never captured.
How do I convert inches or millimetres to pixels?
Multiply by the DPI. At 300 dpi, 2 inches is 600 pixels, and 35 mm is 35 ÷ 25.4 × 300 ≈ 413 pixels. The print presets do this for you, and the passport photo maker applies the official figure for each country.
What is the difference between resizing and compressing?
Resizing changes how many pixels there are. Compressing changes how precisely each pixel is stored. If a form asks for “600×600 pixels, under 240 KB”, you need both — resize first, then compress to the target size, or chain the two with one click from the result screen.
Can I resize a batch to the same dimensions?
Yes. Every file in the batch gets the same setting, and each is processed independently in a background thread.
Does it keep the aspect ratio?
By default, yes — set a width and leave the height empty and the height follows. Untick “Keep aspect ratio” to force exact dimensions, and then choose whether to crop, letterbox or stretch.
What is the largest image it can handle?
There is no imposed limit. In practice, browsers cap canvas dimensions somewhere around 16,000 pixels per side on desktop and lower on mobile Safari, and very large images will use a lot of RAM. Files over 300 MB trigger a warning before processing starts.