How to resize an image
- Add your image. Drop a JPG, PNG or WebP file into the editor above, choose it from your device, or paste it with Ctrl/⌘+V.
- Enter the new size. Type a width or height in pixels. With Keep aspect ratio switched on, the other value updates automatically so the picture is not stretched.
- Or use a quick size. Choose 25%, 50% or 75% of the original, a common web width, or an exact social media format such as 1080×1350 for an Instagram portrait post.
- Apply and download. Click Apply resize, then choose the output format and quality in the Download panel. You see the final dimensions and file size before saving.
Resizing vs. cropping vs. compressing
These three words are often mixed up, but they do different things:
- Resizing changes the number of pixels. A 4000×3000 photo resized to 1200×900 shows the same scene with less detail and a much smaller file.
- Cropping cuts away part of the picture. Use the Crop tool when you want a different shape or framing.
- Compressing keeps the dimensions but stores the pixels more efficiently. Use the Compress tool when a site or form limits the file size in KB.
The fixed-size presets (for example 1080×1080) combine resizing with a centered crop, so the result fills the target size exactly without distortion.
Which size should I choose?
| Use | Recommended size |
|---|---|
| Full-width website hero image | 1920 px wide (1600 px is often enough) |
| Image inside a blog article | 1200–1600 px wide |
| Email attachment or newsletter | 800–1200 px wide |
| Instagram square / portrait | 1080×1080 / 1080×1350 |
| Story, Reel, TikTok | 1080×1920 |
| Link preview (Facebook, LinkedIn, X) | 1200×630 |
| YouTube thumbnail | 1280×720 |
For a longer list with explanations, see our social media image size guide.
Tips for sharp results
- Make images smaller, not bigger. Enlarging a small picture cannot add detail that was never captured, so it will look soft. Start from the largest original you have.
- Resize before you compress. A photo that is the right size for its purpose is usually small enough already, and needs far less compression.
- Use high-DPI sizes for screens. If an image is shown 600 px wide on a web page, exporting it at 1200 px keeps it crisp on phones and Retina displays.
- Keep the original. Tools4U never overwrites your file — the download is a new copy — so you can always go back and try another size.
Our resizer scales large reductions in several half-size steps with high-quality smoothing, which keeps fine detail and text cleaner than a single jump from a huge photo to a small thumbnail.