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Celveri

Image Resizer

Change an image's pixel dimensions for an upload box, a page layout or a print size. Your image is processed in this browser tab.

Resize an image

Drag an image here, or choose one

JPEG, PNG, WebP, GIF, BMP or AVIF, up to 25.00 MB.

Your image is processed in this browser tab. It is not uploaded.

How to use it

  1. Drag an image onto the box above, or choose one from your device.
  2. Type a new width or height. With Keep the original proportions ticked, the other box follows automatically.
  3. Or switch to Scale by percentage for a quick half-size or quarter-size version.
  4. Check the output format, then select Resize image and download the result.

What this tool does and does not do

It changes the pixel dimensions of your image by redrawing it at a new size. That is a different job from compression: resizing changes how many pixels there are, and re-encoding the result can affect how the image looks.

  • A smaller file is likely, not guaranteed. Format and quality affect the size as much as the dimensions do. The tool shows the real result and says when it is not smaller.
  • Quality changes. Shrinking discards pixels, and saving as JPEG or WebP re-encodes the image, so the result is never identical to the original. Enlarging cannot add detail.
  • Proportions are protected. With the lock on, the tool recalculates the other side rather than stretching the image. Calculated sides are rounded to whole pixels.
  • Transparency is kept when the output is PNG or WebP, and you are warned before JPEG would flatten it.
  • Limits. Input files up to 25.00 MB; output up to 16,384 pixels on a side and 40 megapixels in total, because the whole image is held in your browser’s memory.
  • Metadata is removed and animated files are reduced to their first frame.

Resizing or compressing?

Resize when the dimensions are what matter: an avatar that must be 512 pixels square, a header image for a page, a photo that is far larger than it will ever be displayed. Compress when the file size is what matters: an upload box that refuses anything over 2 MB, or an email attachment limit. The Image Compressor aims for a target size directly.

Common questions

Will resizing make the file smaller?
Usually, but not always. Fewer pixels normally means a smaller file, yet the format and quality matter just as much: saving a small PNG at maximum quality can easily be larger than the JPEG you started with. The tool reports the actual size either way, and says plainly when the result is not smaller. If a specific file size is what you need, the Image Compressor aims for one directly.
What does “keep the original proportions” do?
It links the two boxes. Type a width and the height is recalculated from the original image’s shape, and the other way round, so the picture is never stretched or squashed. Turn it off if you deliberately want to distort the image or fit an exact box.
Why is my resized image slightly off the number I typed?
With the proportions locked, the calculated side is rounded to a whole pixel, because images cannot have a fraction of one. On an unusual aspect ratio that can be a pixel away from the exact ratio. Turn the lock off to set both numbers exactly.
Can I make an image bigger?
You can, and the tool warns you when you do. Enlarging cannot invent detail that was never captured, so the result looks softer or blockier than the original. Nothing here uses AI to add detail.
Is transparency kept?
Yes, when the output format supports it. PNG and WebP both store transparency and it survives the resize. JPEG cannot, so if you choose it the tool warns you first and fills transparent areas with white.
Is my image uploaded anywhere?
No. The image is decoded, redrawn at the new size and re-encoded by your own browser, and the download comes from the copy made in the tab. Celveri has no upload endpoint and no database. You can watch your browser’s network tools while you resize to confirm it.

Other image tools

  • Image Compressor

    Reduce an image to a target file size such as 100 KB or 500 KB.

  • Image Format Converter

    Convert between the image formats your browser can genuinely decode and encode.

  • Image Cropper

    Crop to the part of a picture you want and download the result.