Resizing changes pixel dimensions, not just how large an image appears on screen. A local resize tool decodes the source, resamples pixels, and exports a new file without sending the image to a server.
The best settings come from the destination. A profile picture, email attachment, responsive website image, and print asset need different dimensions. Decide the use case first, then protect aspect ratio and inspect the result at its real display size.
Choose target dimensions from the destination
For web use, resize near the largest rendered CSS size multiplied by the expected device pixel ratio. For a 600-pixel layout slot on a 2x display, a 1200-pixel source can be reasonable. Avoid keeping 4000 pixels just because the camera produced them.
Preserve aspect ratio unless cropping is intentional
Locking aspect ratio prevents stretching. If a destination requires a square or fixed banner ratio, crop intentionally before resizing. Changing width and height independently distorts faces, logos, and text.
Understand downscaling and upscaling
Downscaling combines source pixels and usually produces a smaller, cleaner file. Upscaling creates additional pixels through interpolation or a model but cannot recover detail that was never captured. Sharp graphics may need a different resampling mode from photographs.
Select output format and quality
Keep PNG when transparency or sharp interface edges matter. Use JPEG or WebP for photographs when smaller size is important. After resizing, moderate quality often reduces the file substantially without visible loss. Avoid repeatedly exporting a lossy result.
Verify local processing and export
Use the Network panel with a sample to confirm no upload occurs. Preview the output at 100 percent, check orientation and transparency, compare file size, and save with a new name. Keep the original until the resized file has been used successfully.
Summary
Local image resizing is safest and most effective when the destination determines the pixel dimensions. Preserve aspect ratio, crop deliberately, choose a format for the content, inspect at real size, and keep the original.