UtilibyWritten by the Utiliby editorial team · Last updated October 13, 2026 · Rules and formulas reviewed October 2026
What this free image resizer does
Every image has a size in pixels, and every use has a size it wants: a profile picture, a blog header, a product photo, a form that asks for 600 by 600, a print at 4 by 6 inches. An image resizer changes the pixel dimensions of a picture to fit. This free online tool does it in your browser, with exact sizes, percentages, social media presets, and units in pixels, centimeters, millimeters or inches.
You can resize many images at once, keep the proportions or fill a fixed shape, set a target file size such as 200 KB, change the format, and download a ZIP. Nothing is uploaded, and there is no watermark.
How to resize an image in four steps
- Add your images. Drag them onto the drop area or click to choose files.
- Choose how to resize. Type an exact width or height, pick a percentage, or choose a preset such as Instagram or YouTube.
- Set the output. Keep the format or switch to JPG, WebP or PNG. Add a target size in KB if a form requires it.
- Download. Save one image, or press Download resized images to get a ZIP.
Pixels, centimeters and dpi
A digital image has no physical size until it is printed. The link between pixels and centimeters is the resolution, measured in pixels per inch (dpi). The formula is simple: pixels = inches x dpi, and one inch is 2.54 centimeters.
| Print size | At 300 dpi | At 150 dpi |
|---|---|---|
| 4 x 6 in (10 x 15 cm) | 1200 x 1800 px | 600 x 900 px |
| 5 x 7 in | 1500 x 2100 px | 750 x 1050 px |
| 8 x 10 in | 2400 x 3000 px | 1200 x 1500 px |
| A4 (210 x 297 mm) | 2480 x 3508 px | 1240 x 1754 px |
| A5 (148 x 210 mm) | 1748 x 2480 px | 874 x 1240 px |
| Passport 35 x 45 mm | 413 x 531 px | 207 x 266 px |
300 dpi is the usual target for photo prints. Screens do not use dpi, only pixel size, so for the web just set pixels.
What happens when the shape is different
If you need a fixed width and a fixed height, for example 1080 by 1080, and your picture is not square, something has to give. The tool offers four ways to handle it:
- Fill and crop: scales the picture up until it covers the box, then trims the overhang from the center. No bars, but the edges are cut.
- Fit inside: scales the whole picture to fit inside the box. The result may be smaller than the box in one direction.
- Fit and add padding: as above, but adds bars in a color you choose so the final size is exact.
- Stretch: forces the exact size and distorts the picture. Use it only for abstract images.
Resizing for websites, social media and email
- Websites: resize to the largest size the image is actually shown. A blog column of 800 pixels does not need a 4000 pixel photo. Smaller images load faster.
- Social media: use the preset list. Platforms recompress images on upload, so start with the exact recommended size.
- Email: 1000 to 1600 pixels on the long side is enough for most screens, and it keeps attachments small.
- Online forms: some portals ask for a size such as 600 by 600 pixels and a maximum of 200 KB. Set both here.
Keeping quality when you resize
Scaling an image down by a large factor in one step can make it look jagged. This tool scales in smooth halving steps with a high-quality filter, which keeps edges clean. Scaling up is different: the tool must invent pixels, so the result looks soft. As a rule, do not enlarge a picture by more than about 150 to 200 percent, and use the highest-resolution original you have.
JPG and WebP add a small amount of compression loss every time you save them, so resize from your original rather than from an already resized copy.
Common uses
- Profile pictures and avatars for sites and apps with fixed sizes.
- Product photos for shops and marketplaces that require a certain pixel size.
- Application and visa forms with size and file limits.
- Blog and website images sized to the layout.
- Print orders sized to a paper size at 300 dpi.
- Thumbnails and icons at 512 or 256 pixels.
Troubleshooting
- The picture looks stretched: tick Keep aspect ratio, or choose Fill or Pad instead of Stretch.
- The picture looks soft: you enlarged it. Use a bigger original.
- The file size is too big: add a Target size in KB, or lower the pixel size as well.
- The size in centimeters is wrong: check the dpi. The same pixels print smaller at a higher dpi.
- An image failed: the size may be too large for your browser, or the format may be unsupported. HEIC opens only in Safari.
Online resizer or desktop software?
Photo editors offer resampling choices such as Lanczos and bicubic sharpening, and batch scripts handle thousands of files. For everyday resizing, a browser tool is quicker, requires no installation, handles many files at once and keeps your pictures on your device. For a large archive or exacting print work, desktop software gives finer control.
Privacy and how it works
Your browser decodes each image and redraws it at the new size, in steps when the reduction is large. For JPG and WebP the browser's own encoder writes the file at your chosen quality. The page then adds the dpi label. Nothing is uploaded, stored or logged. The saved files contain no EXIF data.
Frequently asked questions
How do I resize an image online for free?
Drop your image into the tool, choose how to resize (exact size, percentage or a preset), and the result appears right away. Then press Download. You can add many images and download them together as a ZIP. Everything runs in your browser.
Are my images uploaded to a server?
No. Your images are opened and resized on your own device. Nothing is sent to Utiliby or any other server.
How do I resize an image to a specific size in pixels?
Choose Exact size, keep Pixels as the unit, and type the width and height. With Keep aspect ratio ticked, change one side and the other follows. Untick it if you need a fixed width and height, then choose how to handle a different shape.
How do I resize an image in centimeters or inches?
Switch the unit to centimeters, millimeters or inches and set the resolution, for example 300 dpi for printing. The tool converts to pixels: 10 cm at 300 dpi is about 1181 pixels. The dpi value is also stored in the saved file.
What does Keep aspect ratio do?
It keeps the width-to-height proportion of the picture, so it does not look stretched or squashed. If you enter both sides, the picture is scaled to fit inside that box.
What is the difference between fill, fit, pad and stretch?
They decide what happens when the new shape is different from the original. Fill scales up and crops the edges so the box is fully covered. Fit scales the picture to fit inside with no crop. Pad fits it and adds colored bars. Stretch changes the shape to match exactly.
How do I resize an image to 100 KB or 200 KB?
Set the size you need, then type a Target size in KB. The tool finds the highest JPG or WebP quality that stays under the limit. If the picture is still too big, make the pixel size smaller too.
Does resizing reduce the quality?
Making a picture smaller keeps it sharp, because the tool scales down in several smooth steps. Making it bigger cannot add detail, so it looks softer. JPG and WebP also lose a little detail when saved, so use a high quality for important images.
Can I resize many images at once?
Yes. Drop several images and the same settings apply to all of them. You can download each one or all as a ZIP. With Keep aspect ratio, each image keeps its own shape.
What size should I use for Instagram, YouTube or Facebook?
Use the Social media or preset size list. It includes common sizes such as 1080 by 1080 for Instagram posts, 1280 by 720 for YouTube thumbnails and 1200 by 630 for link previews. Platforms change these now and then, so check their current guides.
Can I make an image bigger?
You can, by setting a larger size or percentage. The picture is enlarged smoothly, but it will not gain detail. Tick Do not enlarge small images to leave smaller pictures as they are during a batch.
What does the resolution (dpi) setting do?
It writes a print resolution label into the JPG or PNG file. It does not change the number of pixels. Print programs use it to decide how large the image prints. For the web, the dpi number does not matter.
Can I change the file format while resizing?
Yes. Choose JPG, WebP or PNG in the Save as list, or leave it on Same as input. Transparent areas are filled with the padding color when you save as JPG.
Is there a limit on image size?
There is no fixed limit, but very large images need a lot of memory. The tool stops if the new size is too large for your browser. Phones may fail on photos above about 16 megapixels.
Is the transparent background kept?
Yes, for PNG and WebP. JPG cannot be transparent, so transparent areas are filled with white or your chosen padding color.
Does resizing remove EXIF data and location?
Yes. The resized image is saved fresh, without camera details, dates or GPS location. The picture's orientation is applied, so it still appears upright.
What can I print or save from the page?
Print / save summary gives a table of file names, original and new sizes and your settings. Copy summary copies the same table as text. The resized images are the main download.
Sources and further reading
- MDN Web Docs, Canvas API and imageSmoothingQuality, for how browsers scale images.
- W3C, PNG Specification, physical pixel dimensions (pHYs chunk), for how dpi is stored in PNG files.
- JFIF specification, density units and pixel density fields, for how dpi is stored in JPEG files.
- ISO 216, paper sizes (A series), for the A4 and A5 dimensions in millimeters.
- Meta Business Help Center and YouTube Help, current image size guidance for posts, covers and thumbnails.
Sources were consulted in October 2026. Standards and rules can change, so always check the official page for your situation.