Whether you are uploading a photo to a website, sending it by email or posting it online, you often need to change its size. Done badly, resizing makes images blurry or pixelated. Here is how to do it properly.
Resizing vs Compressing
Resizing changes the dimensions of an image, such as its width and height in pixels. Compression reduces the file size, often by removing some detail. They are related but different, and you may need one or both.
Why Images Lose Quality
- Enlarging small images: making a small image bigger forces the software to guess new pixels, which looks soft or blocky.
- Ignoring the aspect ratio: stretching width and height by different amounts distorts the picture.
- Repeated saving: saving a JPEG again and again gradually degrades it.
- Over-compression: a very low quality setting leads to visible artefacts.
Step-by-Step: Resize an Image
- Keep a copy of the original file.
- Open a resizer tool. You can use our free image resizer.
- Upload your image and enter the new width or height.
- Keep “maintain aspect ratio” ticked so the picture is not distorted.
- Resize, preview the result and download it.
Always Scale Down, Not Up
Reducing an image keeps it sharp because you are removing pixels rather than inventing them. If you know you need a certain size, start with a larger original.
Choosing the Right Size for the Web
- Full-width banner images: typically around 1200 to 1920 pixels wide.
- Blog images: about 800 to 1200 pixels wide is usually enough.
- Thumbnails: a few hundred pixels.
Oversized images slow your website down, which hurts user experience and search performance.
Choosing the Right Format
- JPEG: best for photographs.
- PNG: best for graphics, logos and images that need transparency.
- WebP: a modern format that offers smaller files with good quality, supported by modern browsers.
Tips for Sharper Results
- Resize once from the original instead of repeatedly resizing copies.
- Do not push compression too far.
- Check the image at the size people will actually see.
- Add descriptive alt text when you publish it on a website.
Final Thoughts
Keep the original, preserve the aspect ratio, scale down rather than up and choose an appropriate format. Follow these rules and your images will stay sharp and load quickly.