Understand why enlarging a small image can look blurry, how to choose a sensible output size and when a higher-resolution original is needed.
Enlargement changes dimensions, not captured detail
A small image contains a limited set of pixels. Enlarging it spreads that information over a larger output, with additional pixels estimated between the originals. A file can therefore become 2000 pixels wide without containing the detail of a photograph originally captured at that width.
ToolNivo Image Resizer uses ordinary browser image scaling. It is not an AI upscaler and does not invent a sharper version of faces, lettering or textures. Expect visible softness when a small source is enlarged substantially.
Compare the original at its natural size
Check the dimensions displayed when you select the source. If it is only 300 by 200 pixels, inspect it at that size before requesting a much larger result. Blurred text or compression damage already visible in the original cannot be repaired simply by entering larger dimensions.
Look for another source copy, such as the original camera image or a larger export from the design project. A screenshot of a small preview often contains less detail than the actual source file. Use the best available original rather than repeatedly enlarging a resized version.
Separate stretching from softness
If shapes look distorted as well as blurry, verify that Preserve aspect ratio is enabled. A proportional enlargement can still look soft, but it should not turn a circle into an oval. These are different problems and require different corrections.
Try a smaller output that fits the intended placement more realistically. If the destination truly requires a large detailed image, replacing the source may be the only useful solution. A larger filename size is not evidence that quality has improved.
Inspect the exported result
Download the image and view it at the size in which other people will see it. Check readable text and recognizable features, not just the pixel dimensions. Keep the output only when it is suitable for the task; otherwise use a smaller placement or obtain a higher-resolution original.