You can change an image’s dimensions by setting a new width or height while keeping its proportions locked. Then compare the result with the original and check the downloaded file before using it.
Resize an image step by step
- Open Image Resizer and choose one JPG/JPEG, PNG or WebP image. The file must be no larger than 25 MiB. Resizing happens locally in your browser.
- Read the original width and height. Both fields start with the source dimensions.
- Leave Keep proportions on. Enter a new width or height; the other dimension recalculates from the original aspect ratio, rounded to a whole pixel. Alternatively, choose the 50% or 75% preset. For example, a 2,000 × 1,200 image becomes 1,000 × 600 at 50% or 1,500 × 900 at 75%.
- Click Resize image. Compare the original and output previews, dimensions and displayed file sizes.
- Download the result, then open the saved file and check its dimensions and appearance. Look closely at text, edges and any transparent areas.
The source and target must each be no more than 12,000 pixels on either side and 32 million pixels in total. Target dimensions must be positive whole numbers and must differ from the original.
Avoid common mistakes
- Don’t unlock proportions unless you need to. Changing width and height independently can stretch or squash the image. If you need an exact shape that has a different aspect ratio, resizing alone may not produce the composition you want.
- Don’t expect enlargement to recover detail. Increasing dimensions can make an image look less sharp. The tool warns when either target dimension exceeds 125% of its original size, but smaller increases can also affect appearance.
- Don’t assume smaller dimensions mean fewer bytes. Re-encoding can make the output file larger or smaller. If your main goal is reducing file size rather than changing dimensions, use Image Compressor instead and check its result.
- Don’t skip the saved-file check. The tool attempts to save in the source format, but browser support can affect the result. PNG or WebP transparency may survive; inspect it in the downloaded file. Camera metadata may not survive re-encoding, and animation preservation is not guaranteed.
Frequently asked questions
Will resizing an image reduce its file size?
Not necessarily. Changing pixel dimensions and reducing file bytes are different goals, and re-encoding can increase or decrease the file size. Use Image Compressor when reducing bytes is your main goal.
Can I make an image larger without losing quality?
Enlarging cannot restore detail that was not in the original, and the result may look less sharp. Compare the preview and inspect the downloaded image.
Will a transparent or animated image stay that way?
PNG and WebP transparency may survive where browser support allows, but animation preservation is not guaranteed. Check the downloaded file.
Is my image uploaded for resizing?
Image Resizer processes the image locally in your browser without uploading it for resizing.