URLTO GUIDE
Prepare web images: resize, compress and choose a format
Resizing, reducing file size and changing format solve different problems. Decide the display context and required quality before exporting.
URLTO editorial · Updated
Image resizing · series01 / 10
1. Select the operation that fits the job
| Operation | What changes | Example |
|---|---|---|
| Resize | Reduce pixel dimensions while preserving aspect ratio | 2400 × 1600 → 1200 × 800 |
| Compress | Keep dimensions and choose output format and quality | Compare JPEG or WebP quality |
| Convert | Choose PNG, JPEG or WebP output | Review a transparent PNG exported to JPEG |
2. Decide the required dimensions first
Resize fits an image within the maximum width and height while preserving its aspect ratio and never upscaling a smaller original. A 2400×1600 source fitted within 1200×1200 becomes 1200×800. It is not a square crop, so check how the publishing layout crops it separately.
3. Review format, quality and transparency
JPEG output fills transparent areas with white. PNG does not use the quality slider in the same way; compare JPEG and WebP quality visually. An exported file is not guaranteed to be smaller. Inspect small text, logo edges and photo detail at the intended display size.
Images are redrawn and exported in the browser, so do not rely on preserving original metadata or animation. Keep the original and use an appropriate workflow when those properties matter.
4. Inspect the output before replacing a published image
Inputs must be PNG, JPEG or WebP up to 20 MB, 20 megapixels and 8192 pixels per side. Processing does not upload the source image to the server. Review dimensions, file size, background and clarity in the downloaded output. For a sharing card, also inspect its public image URL in Social Preview.