Free image resizer.
Set an exact image width or height, keep the aspect ratio, and download a resized image without uploading it.
Resize for product listings, profile photos and web pages. Proportions stay locked by default.
Images stay on your device. Browser export support varies: PNG ignores the quality slider, JPEG turns transparency white. Compression does not always mean a smaller file; check the actual result.
How to use this tool
- Choose a PNG, JPEG or WebP file. The image stays on your device.
- Enter the desired pixel width or height; keep the aspect ratio locked unless you want to stretch it.
- Choose WebP, JPEG or PNG and click Resize image. Check the size and download the result.
Good to know
Resizing changes pixel dimensions, not just file size. Enlarging a small image cannot recover missing detail. Use WebP or JPEG for photographic website images; PNG preserves transparency.
This utility processes its content locally in your browser. No usage counter is required while public tools are free and unlimited. As with any online tool, avoid entering sensitive information on devices you do not trust.
Choosing image dimensions for a website
Pixel dimensions and file size solve different problems. A 4000 × 3000 photograph displayed in a narrow article column can be resized before upload, so the visitor does not download pixels they cannot use. Start by checking the actual width at which the image appears in your layout.
For a picture that appears around 800 CSS pixels wide, a 1600-pixel version can provide sharper detail on a higher-density screen. That is a practical example, not a universal rule: your layout, crop and responsive image setup determine the right sizes. Generate a few properly sized variants if you use srcset rather than forcing one very large file everywhere.
Resize before you compress
Resizing changes the number of pixels. Compression changes how image information is stored. A large photo often benefits from both: first make it the right dimensions, then choose an efficient format and quality.
Keep aspect ratio enabled for portraits, product photos and logos unless you deliberately want to stretch the image. RezSat will show the expected output dimensions before you process the file.
Picking WebP, JPEG or PNG
For photographic content, WebP or JPEG is usually a sensible place to start. For graphics where exact pixel edges or transparency matter, try PNG. Converting a low-quality image into PNG does not recreate missing detail.
The actual pixel conversion happens in your browser using Canvas; your image is not uploaded to RezSat Tools. Large photos may still be limited by the memory available on your phone or computer.
Questions about free image resizer
Does resizing make an image blurry?
Shrinking often preserves a useful appearance, especially for display at the smaller size. Enlarging cannot recreate missing detail. Keeping the aspect ratio prevents stretching.
Can I resize without changing the aspect ratio?
Yes. Leave Keep original aspect ratio checked. Changing width then automatically adjusts height, and vice versa.
Can I resize a PNG and keep transparency?
Yes, choose PNG or WebP. Exporting to JPEG adds a white background because JPEG has no alpha transparency.