How to Resize an Image
Resizing is the single most effective thing you can do to an oversized image, and it's routinely done badly. Drop your files above and choose how you want to specify the new size: exact pixels, or a percentage of the original. With the aspect ratio locked — which it is by default — you enter one dimension and the other is calculated for you, so nothing ends up stretched or squashed. Unlock it only when you genuinely want to force a specific shape. The preset row covers the dimensions people actually need, from an Instagram square to a YouTube thumbnail, and sets both numbers with the lock released so the result matches the platform exactly. You also choose the output format, which matters more than people expect: a photo resized and saved as JPEG at quality 90 will be far smaller than the same image as PNG, while PNG is the right choice for anything with transparency or sharp text. Scaling uses the browser's highest-quality smoothing, so downscaled images stay clean rather than jagged. Resize a whole folder at once, change the settings and re-apply to the entire batch, then take the results individually or as a single ZIP. Everything happens on your device.
Add your images
Drag and drop, paste, or click to browse — multiple at once.
Set the size
Pixels or percentage, with the ratio locked or a preset applied.
Download
Save each image, or take the whole batch as one ZIP.
Resizing vs Compressing
Resizing changes dimensions
Fewer pixels means a smaller file, and the reduction is dramatic — halving the width and height removes three quarters of the pixels. If an image is displayed at 800 pixels wide, storing it at 4000 is pure waste.
Compressing changes quality
Compression keeps the dimensions and discards detail instead. It helps, but resizing first almost always gives a bigger saving with less visible damage — do both, in that order.
Common Use Cases
Shrink camera photos
A 24-megapixel photo is far larger than any web page needs.
Fit an upload limit
Forms and portals often cap dimensions as well as file size.
Social media posts
Match the exact dimensions each platform expects with one tap.
Speed up a website
Serving correctly sized images is one of the biggest Core Web Vitals wins.
Email attachments
Reduce dimensions so the message doesn't bounce.
Product thumbnails
Batch-resize a catalogue to consistent dimensions.
Profile pictures
Resize to the square size a platform requires.
Presentations
Cut slide deck size by resizing images to what's actually displayed.
Tips & Best Practices
Keep the aspect ratio locked
Unlocking it stretches the image. Use a preset or crop first if you need a specific shape.
Never enlarge if you can avoid it
Scaling up invents pixels that were never captured, so the result always looks soft.
Resize before compressing
Removing pixels saves more than lowering quality, and does less visible damage.
Double the size for retina screens
An image displayed at 400 pixels should be exported at 800 to look sharp on high-DPI displays.
Choose the format deliberately
JPEG for photos, PNG for transparency and sharp text, WebP when you want both smaller and modern.
Keep the original
Resizing discards pixels permanently, so archive the full-size file before you overwrite it.
Troubleshooting
My image looks stretched
The aspect ratio lock is off, or a preset set both dimensions. Turn the lock on and enter only one number.
The enlarged image is blurry
Upscaling can't add detail that was never there. Start from a larger original if you need a bigger image.
Transparency turned white
JPEG has no alpha channel. Choose PNG or WebP as the output format to keep it.
The file barely got smaller
Check the output format — saving a photo as PNG keeps it large. Switch to JPEG or WebP.
Frequently Asked Questions
How do I resize an image for free?
Drop your images above, set a width, height or percentage, and download the result — free, no signup and no watermark.
Are my images uploaded to a server?
No. Resizing happens entirely in your browser, so your images never leave your device.
Will it keep the aspect ratio?
Yes, by default. Enter one dimension and the other is calculated so nothing gets stretched.
Can I resize by percentage?
Yes. Switch to percentage mode and scale everything proportionally from 1 to 200 percent.
Can I resize several images at once?
Yes. Add as many as you like and download the whole set as a single ZIP.
Which output format should I choose?
JPEG for photographs, PNG for transparency or sharp text, WebP when you want smaller files and modern support.
Does resizing reduce file size?
Substantially. Halving both dimensions removes three quarters of the pixels.
Can I make an image larger?
You can, but upscaling can't invent detail — the result will look soft. Start from a bigger original when possible.
Is there a file size limit?
No. Nothing is uploaded, so the only constraint is your device's memory.
What are the social media presets?
One-tap dimensions for Instagram, Facebook, X, LinkedIn and YouTube, so you match each platform exactly.
Will it add a watermark?
No. The output contains only your image.
What happens to transparency?
PNG and WebP keep it. JPEG has no alpha channel, so transparent areas are filled with white.
Does it remove EXIF data?
Yes. Canvas-based processing drops metadata, including any GPS coordinates.
Should I resize or compress?
Resize first — it saves more with less visible damage — then compress if you need to go further.
Can I change settings after resizing?
Yes. Adjust anything and press apply new settings to reprocess the whole batch.
Does it work offline?
Once the page has loaded it runs entirely in your browser, so it keeps working without a connection.
Does it work on phones?
Yes, in any modern browser on Windows, Mac, Android or iPhone with nothing to install.
Is this tool really free?
Completely free, forever — no account, no ads and no premium wall.
100% free · No signup · Processed in your browser · Never uploaded
Last updated: August 2026 · FlipMyFormat Image Resizer
Written and maintained by the FlipMyFormat team · Runs entirely in your browser