Resize an image to exact pixel dimensions, understand aspect-ratio settings and check the downloaded result before adding it to a page or design.
Start with the required dimensions
Find the actual width and height requested by your destination. A layout asking for 800 by 600 pixels needs a different shape from one asking for 800 by 800. File size in kilobytes is a separate requirement: setting the dimensions does not guarantee a particular download size.
Check the original dimensions displayed after selecting your image in ToolNivo Image Resizer. A 1600 by 1200 photograph can become 800 by 600 while keeping the same proportions. That is a straightforward reduction because both dimensions are halved.
Set the width and height
Leave Preserve aspect ratio enabled when you want to avoid stretching. Entering a new width updates the height according to the original proportions. Entering a new height similarly updates the width. Values are rounded to whole pixels, so an unusual ratio may produce a one-pixel difference from a manual calculation.
If your destination requires a different shape, this tool cannot crop the photograph to achieve it. Turning off the ratio option allows independent dimensions but stretches the image. Prepare a correctly cropped source in an image editor when distortion is unacceptable.
Choose a usable output format
Select JPEG for a conventional photo copy, PNG when transparency matters, or WebP if your destination accepts it. JPEG fills transparent areas with white. Choose Resize image and look at the generated preview rather than assuming the selected numbers are sufficient.
The current output limit is 8,000 pixels per side and 24 megapixels in total. For example, 6000 by 4000 fits the pixel limit, while 8000 by 8000 does not. Very large files can also exceed the memory available on a phone.
Verify the downloaded image
Download the result and inspect its dimensions in your device's file details or image editor. Check faces, circles and lettering for unexpected stretching. Keep the source image separately so that you can create another size without resizing an already reduced copy.