How to use Image Resizer
- 1Drop in one image, or several to resize as a batch
- 2Type a width or height, drag the scale slider, or pick a preset
- 3Leave the chain icon locked to keep the original proportions
- 4If your target shape differs from the original, choose Stretch, Fit inside or Fill & crop
- 5Download the resized image, or the batch as a ZIP
What Image Resizer does
Resizing an image means resampling it: the new grid of pixels rarely lines up with the old one, so every output pixel has to be worked out from several input pixels. Doing that badly is what produces the jagged edges and shimmering fine detail people associate with a resized photo — and it is why the same image resized in two different programs can look noticeably different.
Shrinking is the harder direction. A browser asked to draw a 6000-pixel-wide photo straight into a 400-pixel box samples too few source pixels for each target pixel and aliases badly, even with smoothing turned on. This tool halves the image repeatedly first and only then makes the final draw, so detail averages down smoothly instead of being point-sampled away.
When to use it
- Uploads with fixed dimensions
- Job boards, ID portals and marketplace listings often demand an exact pixel size and reject anything else. Typing the two numbers directly is faster and more reliable than cropping by eye in a photo app.
- Photos straight off a phone
- A modern phone camera produces images around 4000 pixels wide. For a blog post, an email or a slide, anything past about 1600 pixels is invisible detail that only costs load time.
- Social media in the right shape
- Instagram, Story and avatar presets set both dimensions at once. Because those shapes differ from a normal camera frame, the fit controls decide whether the image is padded or cropped to reach them.
- A whole folder at one scale
- In batch mode the numbers you type are read as a scale factor rather than fixed dimensions, so a set of mixed portrait and landscape photos all shrink by the same proportion and each keeps its own shape.
Image Resizer settings explained
- Width and height (px)
- Exact output dimensions. With the chain icon locked, editing one recalculates the other from the original proportions. Unlock it to set both independently, which is when the aspect handling controls appear.
- Scale
- A percentage slider from 5% to 200% that drives both dimensions at once. Useful when you want an image roughly half its size and do not care about the exact pixel count.
- Presets
- One click for the six sizes that come up most: HD 1920×1080, 4K 3840×2160, Instagram 1080×1080, Story 1080×1920, Avatar 512×512 and Thumbnail 320×320.
- Aspect handling
- Only appears when your target shape differs from the original. Stretch distorts the image to fit exactly, Fit inside keeps everything and pads the gaps with a colour you choose, Fill & crop covers the frame and trims the overflow.
- Do not upscale
- On by default. Enlarging cannot add detail that was never captured, so a request larger than the original is quietly reduced to the original size instead of producing a soft, blown-up image.
Stretch, Fit inside or Fill & crop
| Mode | Keeps the whole image | Distorts | Result |
|---|---|---|---|
| Stretch | Yes | Yes | Exact dimensions, squashed or stretched |
| Fit inside | Yes | No | Exact dimensions with padding bars |
| Fill & crop | No | No | Exact dimensions, edges trimmed |
Limits and what to expect
- 100 MB per file, 50 files per batch and 300 MB per queue.
- Images beyond roughly 100 megapixels are refused, because an oversized browser canvas renders blank rather than reporting an error.
- Enlarging is capped at 200% and disabled entirely while Do not upscale is on — no detail can be invented.
- Output is encoded at 92% quality for lossy formats, high enough that resizing is not a second round of visible compression.
- Animated GIFs lose their animation; only the first frame is resized.
Troubleshooting
- The image looks squashed
- The aspect ratio lock was off and the target shape differs from the original, so Stretch was applied. Switch to Fit inside to pad instead, or Fill & crop to trim, or re-lock the chain icon to keep the proportions.
- Nothing happened when I asked for a bigger image
- Do not upscale is on, so the request was reduced back to the original size. Turn it off if you genuinely need a larger canvas, but expect the result to look soft — the extra pixels are interpolated, not real detail.
- White bars appeared around the image
- That is Fit inside padding the difference between your target shape and the original. Change the padding colour to match your background, or use Fill & crop if you would rather lose the edges than see bars.
- In batch mode the images came out different sizes
- That is deliberate. The numbers you typed describe the first image and are applied to the rest as a scale factor, so portrait and landscape photos in one queue keep their own shapes rather than all being forced into one frame.
Your files and your privacy
Resizing happens on a canvas inside your browser tab, using your own device's graphics stack. The image is never uploaded, never written to a server and never queued anywhere for later processing. Batch jobs are zipped in the tab as well, so even a 50-file queue stays on your machine from start to finish.
What to use next
FAQ
How do I resize an image without losing quality?
Shrinking is safe: the tool halves the image progressively before the final draw, which averages detail down smoothly instead of point-sampling it. Enlarging is different — no tool can recover detail the camera never captured, so anything past 100% will look softer than the original however it is done.
What is the difference between resizing and cropping?
Resizing changes the pixel dimensions of the whole image and keeps every part of it. Cropping keeps the original pixel density but throws away the edges. Fill & crop mode does both at once: it scales to cover your target shape, then trims whatever hangs over.
What size should an image be for a website?
For a full-width banner, 1920 pixels wide is plenty; for an in-article image, 800–1200 is usually enough. Serving anything larger than the space it will occupy wastes load time with no visible benefit, which is why the HD preset suits most web work.
Can I resize several images at once?
Yes, up to 50 files within 300 MB. The dimensions you enter describe the first image and are applied to the others as a proportional scale, so each keeps its own aspect ratio. The results download together as a ZIP.
Will resizing change my image format?
No. A JPG stays a JPG and a PNG stays a PNG. The one exception is a transparent image being written to a format that cannot store transparency, in which case the transparent areas are filled with your chosen padding colour first.
Why is my resized file still large?
Resizing reduces pixel dimensions, not compression. A 1920-pixel photo saved at high quality can still be several megabytes. Run the result through the image compressor afterwards if file size rather than dimensions is what you are trying to control.