Image Resizer

About the Image Resizer

This free image resizer changes the dimensions of a JPG, PNG or WebP. Set an exact width and height, keep the proportions locked, or scale by percentage — then download the result.

Everything runs in your browser — your image is never uploaded.

Resizing is not compressing

These two get confused constantly, and they do completely different things.

Resizing changes how many pixels the image has. A 4000 × 3000 photo resized to 1000 × 750 now contains one sixteenth as many pixels. The discarded pixels are gone.

Compressing keeps the same pixel count but stores it more efficiently, accepting some loss of detail to do it.

Resizing is by far the bigger lever, and people reach for it second when they should reach for it first. File size scales with area, not with width — so halving both dimensions leaves a quarter of the pixels, and typically about a quarter of the file size. Compression can rarely achieve that without visible damage.

The most common waste on the web is an image displayed at 800 pixels wide that was uploaded at 4000. The visitor downloads sixteen times more data than their screen can possibly use. Resize first, then compress if it is still too big.

Pixels, aspect ratio, and why locking it matters

Aspect ratio is the relationship between width and height. A 4000 × 3000 photo is 4:3.

Change one dimension without the other and the image stretches. Faces widen, circles become ovals, text leans. There is no partial version of this — it either keeps its proportions or it does not.

Leaving the lock on means typing a width and having the height follow automatically. Turn it off only when you genuinely want to distort the image, which is rare.

If you need an exact size that does not match the original ratio, resize then crop. Resize so the smaller dimension matches your target, then cut the excess off the other. That gives you the exact dimensions with no distortion — the part you do not want is removed rather than squashed. Use Crop Image for the second step.

Making an image bigger does not add detail

Scaling up is not the reverse of scaling down.

When you reduce an image, information is thrown away. When you enlarge it, there is nothing to put back. The software invents the new pixels by averaging their neighbours, which produces a larger image that is softer, not more detailed. Enlarge enough and edges turn mushy and gradients go blocky.

A rough guide: up to about 120% is usually unnoticeable. By 200% the softness is visible. Beyond that it looks obviously upscaled.

If you truly need a bigger version, the right answer is to go back to the original file — the camera's full-resolution image, or the vector source if one exists. An SVG or other vector file has no fixed resolution and can be exported at any size with no loss at all. AI upscaling, which guesses at plausible detail rather than averaging, does better than plain enlargement but is still inventing rather than recovering.

Sizes worth knowing

Common targets, so you are not guessing:

• Website hero image — 1920 × 1080 is plenty; larger is almost always waste
• Blog body image — 1200 wide is generous for most layouts
• Email attachment — 1600 on the long edge keeps it well under most size limits
• Instagram — 1080 × 1080 square, 1080 × 1350 portrait
• Facebook shared link image — 1200 × 630
• YouTube thumbnail — 1280 × 720
• Printing at 300 DPI — multiply inches by 300, so a 6 × 4 inch print needs 1800 × 1200 pixels
• Passport and ID photos — follow the official specification exactly; use Passport Photo Maker rather than guessing

How to use it

• Upload an image — click the upload area or drag and drop
• Set the new size — type a width or height (lock keeps the proportions)
• Download — save your resized image

Good to know

• Keep your original. Resizing down is permanent, and you cannot get the detail back from the smaller copy.
• Resize once, from the original. Repeated resizes each soften the image a little.
• DPI does not affect a screen. For anything displayed on a screen only the pixel dimensions matter; DPI is a print instruction. Use Change Image DPI when a printer asks for a specific value.
• PNG transparency survives the resize; JPG has none to preserve.
• EXIF data is usually dropped, including GPS coordinates. Convenient for privacy, inconvenient if you wanted the camera information.
• Very large images depend on your device's memory, since the work happens locally. A huge panorama may be too much for an older phone.
• Resizing many images? Use Bulk Image Resizer rather than repeating this one.

Common questions

How do I resize an image without losing quality?

Making an image smaller always discards pixels, so some detail is lost by definition — but done once, from the original, at a sensible target size, it is not visible. What causes obvious damage is resizing an already-resized copy, or enlarging. Always go back to the original file rather than working from a version you shrank earlier.

Will resizing reduce the file size?

Yes, and usually far more than you expect, because file size follows the pixel *area*. Halving both width and height leaves a quarter of the pixels and roughly a quarter of the file size. This is why resizing is the first thing to try when an image is too large, ahead of compression.

What is the aspect ratio lock for?

It keeps width and height in proportion, so typing one dimension sets the other automatically. With it turned off you can set both freely, which stretches the image — faces widen and circles become ovals. Leave it on unless you deliberately want distortion. For an exact size that does not match the original proportions, resize first and then crop.

Can I make a small image bigger without it going blurry?

Not really. Enlarging cannot recover detail that is not in the file; the software fills in new pixels by averaging existing ones, which gives a bigger but softer image. Up to about 120% is usually acceptable. If you need a genuinely larger version, go back to the original full-resolution file or a vector source.

What size should my image be for a website?

For a full-width hero image, 1920 pixels wide is ample. For images inside an article, 1200 wide is generous for most layouts. The guiding principle is that an image should not be much wider than the space it is displayed in — serving a 4000-pixel file into an 800-pixel slot makes visitors download sixteen times more data than they can use.

Does resizing change the DPI?

DPI is metadata telling a printer how large to print the image, and it has no effect on screen display, where only pixel dimensions matter. If a print shop asks for 300 DPI, what they need is enough pixels: multiply the print size in inches by 300. A 6 × 4 inch print needs 1800 × 1200 pixels.

Is my photo uploaded to a server?

No. Your browser reads the image, resizes it and hands back the result entirely on your own device. Nothing is transmitted and nothing is stored, so the tool works with your connection switched off.

Related tools

• Crop Image — cut to an exact size without stretching
• Image Compressor — shrink the file further after resizing
• Bulk Image Resizer — resize a whole folder at once
• Compress Image to Size — hit a specific file size target