Image Resizer

Resize Image Online

Resize any image to exact pixel dimensions in your browser. Supports JPEG, PNG, WebP, AVIF and HEIC uploads. Export as JPEG or PNG. Nothing leaves your device.

Last updated: July 2026

Exact

Pixel Size

3 Modes

Fit, Fill, Stretch

Any Format

Support

Private

No Uploads

W
H

Width and height are locked - changing one updates the other to keep proportions.

Scales and crops to fill exact size. No white space. No distortion. Recommended.

85
Smaller fileBetter quality

Drop image here to resize to 1920x1080

JPEG, PNG, WebP, AVIF, HEIC. All processing stays in your browser.

How to resize an image

1

Enter width and height

Type exact pixel dimensions, or start from a preset below.

2

Choose Fit, Fill or Stretch

Pick how the image should scale to the new size.

3

Choose PNG or JPG

JPEG for photos, PNG for transparency or lossless output.

4

Upload your image

Drop a file or click to browse from your device.

5

Download instantly

Nothing is uploaded, the file saves straight to your device.

Understanding resize modes

Fill (default)

Recommended

Scales the image to completely fill the target dimensions while preserving the aspect ratio. Any excess pixels are cropped from the center. No white space, no distortion, this is what most tools do by default.

Good for: Social media posts, thumbnails, wallpapers

Fit

No cropping

Scales the image to fit entirely within your target dimensions while keeping the original aspect ratio. If the proportions differ, white padding is added to fill the remaining space. Nothing is ever cropped.

Good for: Portraits, documents, logos

Stretch

Exact dimensions

Forces the image to exactly match the target dimensions by stretching or squashing. The aspect ratio is not preserved. Use only when distortion is acceptable.

Good for: When exact pixel match is required

What if my image is smaller than the target size?

If your source image is smaller than the target dimensions, the tool will upscale it to reach the requested size. A warning is shown because upscaling raster images reduces sharpness, the algorithm can only interpolate new pixels, it cannot recover detail that was never in the original.

For most use cases (web uploads, social media, document attachments) the result is still perfectly usable. The visual quality difference between a slightly upscaled image and the original is rarely noticeable at normal viewing sizes.

Best practice: Always start from the highest-resolution version of your image when upscaling is required. If you need to increase an image size significantly, the result will be soft and may show artifacts. For AI-quality upscaling, a dedicated upscaling tool with a super-resolution model is needed.

What resizing actually does to your image

Resizing an image is simple, but understanding what happens behind the scenes helps you get better results. Type in the dimensions, click resize, done. And for a lot of use cases, that's exactly right. But there are a few situations where understanding what's happening under the hood saves you from a result that looks worse than it should or causes a submission to fail silently.

When you resize a raster image (a JPEG, PNG, or WebP photo), the software has to either add or remove pixels. Reducing the size is straightforward: pixels are dropped or merged. The image gets smaller and generally looks fine. Increasing the size is harder, because the algorithm has to invent new pixels that weren't in the original. It does this by sampling surrounding pixel values and interpolating. The result is a larger image, but a slightly softer one. At modest upscaling amounts, say 20 to 30%, you probably won't notice. At 2x or 3x, you will.

Pixels vs file size: what you're actually changing

Resizing and compressing are different things, but they're often confused. Resizing changes the pixel dimensions of an image. A 4000 by 3000 pixel photo resized to 1200 by 900 will have fewer pixels and generally a smaller file size, but the exact file size depends on the format and compression settings you choose when saving. Compressing an image reduces the file size by encoding the existing pixels more efficiently, without necessarily changing the dimensions at all.

If you need an image under a specific file size limit (like 100KB for a portal upload), resizing alone might not get you there. You may also need to compress the image separately, or use the main compressor on the homepage, which lets you control both dimensions and quality in one step.

When JPEG is the right output and when PNG is

If you're resizing a photo to share online, send by email, or upload to a portal, output as JPEG, or convert PNG to JPG first if that's your starting format. It produces smaller files and is accepted everywhere. The quality loss from JPEG compression at 80 to 90% is invisible at normal viewing sizes.

Use PNG output when your original image contains transparency or when you want to preserve transparent regions of the image. Note that in Fit mode, any added padding is currently white rather than transparent. PNG is also the right choice for screenshots, diagrams, or images with sharp text, because JPEG compression creates visible artifacts around high-contrast edges like text on a solid background. For those, PNG's lossless encoding keeps the edges clean.

Once the dimensions are right, a few other adjustments often come next. Crop image if you only need part of the frame, change DPI if the image is headed to print rather than a screen, or convert to WebP for a smaller, web-friendly file once you're happy with the size.

Common resizing mistakes

Using Stretch and expecting proportions to stay the same

Stretch forces the exact width and height you type in, even if that distorts the image. If proportions matter, use Fill or Fit instead, or lock the aspect ratio before changing either value.

Upscaling a small image by a large amount

Going from, say, 400x400 to 2000x2000 asks the tool to invent detail that was never in the original photo. The result will look soft. Start from the highest-resolution version you have whenever possible.

Choosing JPEG for an image that needs a transparent background

JPEG doesn't support transparency, so anything transparent gets filled with a solid color on export. If the source has transparency you want to keep, output as PNG instead.

Resizing when the real requirement is file size, not dimensions

A lot of portals actually cap file size in KB, not pixel dimensions. Resizing alone doesn't guarantee you'll land under that limit. Pair it with a compress tool if a form asks for a size like 100KB or 500KB.

Forgetting the aspect ratio lock is off

If you change the width without locking the aspect ratio first, the height won't follow automatically, and Fill or Stretch mode may crop or distort more than expected.

Why use ImgTweak?

Runs entirely in your browser
No uploads, ever
Unlimited use, no daily caps
Batch processing on the main editor
Free forever, no account needed
Works on mobile as well as desktop

Frequently asked questions

What is the difference between fit, fill and stretch resize modes?

Fit scales the image to fit within the target dimensions while preserving the aspect ratio. If the aspect ratios differ, white padding is added. Fill scales the image to fill the target dimensions while preserving the aspect ratio, cropping the center if needed. Stretch forces exact dimensions regardless of aspect ratio and may distort the image.

What happens if my image is smaller than the target dimensions?

The tool will upscale your image to reach the target dimensions. A warning is displayed because upscaling raster images (JPEG, PNG, WebP) reduces sharpness since no new detail can be added. For best results when upscaling is needed, start from the highest-resolution version of your image.

Which output format should I choose, JPEG or PNG?

Choose JPEG for photographs and images without transparency. It produces smaller files and is universally compatible. Choose PNG when the image has a transparent background or when you need lossless quality. Note that in Fit mode, the padding added around the image is currently always white, even when the output format is PNG.

Can I resize while keeping the aspect ratio?

Yes. Enable the aspect ratio lock button between the width and height inputs. When locked, changing either dimension automatically updates the other to maintain the original proportions. Alternatively, use Fit mode, which always preserves the aspect ratio.

Is my image uploaded to a server?

No. All resizing happens entirely in your browser using WebAssembly. Your image never leaves your device.

What image formats are supported?

JPEG, PNG, WebP, AVIF and HEIC are all supported as input. The output is JPEG or PNG depending on your selection.

Does this work on my phone?

Yes. The tool runs entirely in your mobile browser using WebAssembly, so it works on iPhone, Android and tablets without needing an app. Large images may take a couple of seconds longer to process on an older phone.

Can I resize more than one image at once?

This page resizes one image at a time. If you regularly need to resize a batch of images, the main image editor on the homepage supports batch processing across multiple files at once.

Does resizing reduce image quality?

Reducing an image's dimensions rarely causes visible quality loss. Increasing dimensions beyond the original size can soften the image, since the tool has to interpolate pixels that were never in the source photo.

Can I resize an animated WebP or GIF?

This tool works with static images. Animated formats are not supported here, since resizing processes a single still frame rather than preserving the animation.

Can I resize an SVG file?

Not directly on this page, since SVG is a vector format rather than a raster image. Convert it to PNG or JPG first using the SVG converter, then resize the resulting file here.

Is there a maximum image size I can resize?

There is no hard file size limit. In practice, very large or high-megapixel images may take longer to process or struggle on devices with limited memory, since everything runs in your browser rather than on a server.

Does EXIF or GPS data survive resizing?

No. The image is decoded to raw pixels and re-encoded during resizing, so EXIF metadata, including GPS location, does not carry over to the output file.

Can I keep transparency when resizing a PNG?

Yes, PNG output preserves the alpha channel of your original image. The one exception is Fit mode, where any padding added around the image is currently filled white rather than left transparent.

Will resizing reduce my file size?

Usually, since fewer pixels generally means less data. The exact result depends on the format and quality setting you choose. If you need a guaranteed file size limit, pair this with a dedicated compression tool.

Ready to resize your image?

No sign-up. No uploads. Drop your image above and download the resized version in seconds.