Keep Your Image in Proportion
A locked aspect ratio keeps the width and height proportional, so faces, logos and objects aren't stretched or squashed.
Aspect Ratio
KnowAndInvest Tools
Free Online Image Resizer
KnowAndInvest’s free Online Image Resizer lets you resize JPG, PNG, WebP and GIF images to exact pixel dimensions or a percentage of the original — with no sign-up, no watermark and no upload. Your files are processed in your browser and never leave your device.
Last updated:
Before · Original
image.jpg
After · Optimized
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Dimensions
Quick scale
Format
Quality
90%
100% private — nothing is uploaded or stored.
At a Glance
Free Online Image Resizer: Key Facts
- What it does
- Resizes images to exact pixel dimensions or a percentage of the original size
- Cost
- Free — no sign-up and no watermark
- Input formats
- JPG, PNG, WebP and GIF (any image your browser can open)
- Output formats
- JPG, PNG or WebP
- Privacy
- Processed locally in your browser — never uploaded or stored
- Works on
- Desktop, tablet and mobile browsers
Image Essentials
Image Resizing Insights & What to Consider
The right size and format can make all the difference. Keep these essentials in mind when preparing your images.
Choose the Right Dimensions
Smaller dimensions are often enough for a website or social post. Enlarging a small image cannot recreate detail missing from the original.
DimensionsJPG for Photographs
JPG is a practical choice for photos when you want a smaller file. Adjust the quality to balance detail and file size.
JPGPNG for Transparent Images
PNG preserves transparency and uses lossless compression. It's a good choice for logos, graphics and screenshots.
PNGWebP for the Web
WebP supports transparency and efficient compression. It is useful for website images when your destination supports the format.
WebPYour Original Stays Untouched
The downloaded image is a new file. Your original is not overwritten, and your image is never sent to our servers.
Privacy
How It Works
How to Use This Online Image Resizer
Resizing an image online takes four quick steps:
- Select your image. Drag an image into the upload area or click it to browse your device.
- Set the new size. Enter the width and height in pixels, or tap a quick scale such as 50%. Keep the aspect-ratio lock on to avoid stretching.
- Choose format and quality. Pick JPG, PNG or WebP. For JPG and WebP, adjust the quality slider to balance detail and file size.
- Download. Click Download to save a new file. Your original image is left unchanged.
What the Image Resizer Gives You
The image tool displays your original dimensions and file size, along with a preview. Set the exact output dimensions and format you need. For JPG and WebP, you can also adjust quality. The downloaded result is a separate file, leaving your original unchanged.
Image Resizer: Key Settings Explained
Width and height determine the number of pixels in your output. The aspect-ratio lock prevents distortion. Quick scale presets resize relative to the original width. Quality controls compression for JPG and WebP; PNG is lossless and does not use this setting.
Common Image Sizes in Pixels
These are widely used starting points. Platforms update their requirements, so check the current guidelines of where you plan to post.
| Use | Typical size (px) |
|---|---|
| Full HD image or video frame | 1920 × 1080 |
| YouTube thumbnail | 1280 × 720 |
| Instagram square post | 1080 × 1080 |
| Instagram or Facebook story | 1080 × 1920 |
| Link preview (Open Graph) image | 1200 × 630 |
| Profile picture or thumbnail | 400 × 400 |
Deep Dive
More on the Online Image Resizer
The best output depends on where your image will be used. Photographs often work well as JPG, while graphics with transparency are better suited to PNG or WebP. For websites, reducing oversized images can help keep pages lighter.
Resizing and compression are different: dimensions change the number of pixels, while the quality setting changes how much image information is preserved in a compressed file. Reducing both can produce a smaller file, but may also remove detail.
Start with the best original image available, avoid unnecessary enlargement, and check the downloaded result at its intended display size. All changes are applied locally on your device, with no server upload or image storage.
Choosing the Right Format
JPG is a good default for photographs because it keeps file sizes small. PNG preserves sharp edges and transparency, which suits logos, screenshots and graphics with text. WebP can offer smaller files than both for many images and is widely supported by modern browsers.
Sizing Images for Common Uses
Match the output dimensions to where the image will be displayed. A blog or listing image rarely needs to be wider than the content area it sits in, and a profile picture or thumbnail can be much smaller. Exporting at roughly twice the display size is a common way to keep images sharp on high-density screens.
Tips for a Better Result
Resize once from the original instead of repeatedly resizing an already-compressed copy, since each pass can add visible artifacts. Keep the aspect-ratio lock on unless you intentionally want to crop or change proportions elsewhere. If the file is still too large, lower the JPG or WebP quality slightly and compare the result at its real display size.
For more guides on working with images and digital content, visit the KnowAndInvest blog.
Common Questions
Image Resizer FAQs
No. Image processing happens entirely in your browser. Your image files are never uploaded to a server or saved by KnowAndInvest.
Yes. You can resize and download images without signing up or paying, and the tool adds no watermark.
You can open images your browser supports, including JPG, PNG, WebP and GIF, and download them as JPG, PNG or WebP. Animated images are exported as a single still frame.
Open the Online Image Resizer, drop in your image, enter a new width and height in pixels or pick a quick scale (25%, 50%, 75% or 100%), choose JPG, PNG or WebP, then click Download.
Keep the aspect ratio locked. Changing either width or height then adjusts the other dimension automatically.
Reducing dimensions removes pixels. Enlarging an image may make it look softer. JPG and WebP quality settings also affect compression, so always check your downloaded result.
Yes. Choose PNG or WebP when your original image has transparency. JPG does not support transparent backgrounds.
Make the pixel dimensions smaller and, for JPG or WebP, lower the quality slider slightly. Both changes reduce file size, so compare the result at its real display size before using it.
Yes. It runs in modern browsers on desktop, tablet and phone. Tap the upload area and choose a photo from your gallery or files app.
KnowAndInvest does not upload your image, so no server upload limit applies. Very large images are limited only by your browser and your device's memory.
No. Your original image remains on your device. The tool creates a new file for download, so check its dimensions, quality and format before using it.