Practical image guide
How to resize an image without guessing
Resizing changes pixel dimensions; compression changes how efficiently those pixels are stored. They are related, but they solve different problems. If a website asks for 1200 × 630 pixels, resize to those dimensions. If an email service only accepts files below a certain number of megabytes, reduce dimensions first and then adjust export quality.
Work from the best original you have and save the result as a new file. Repeatedly opening and exporting the same JPG can accumulate visible damage, while enlarging a small image cannot recreate detail that was never captured.
Choose dimensions for the destination
- Keep aspect ratio locked unless the destination explicitly requires a different shape. Unlocking it changes the relationship between width and height and can stretch faces, circles, and typography.
- Use the actual display size as your starting point. Sending a 5000-pixel photo into a 700-pixel content column wastes bandwidth without adding visible detail for most visitors.
- For high-density screens, a source around twice the CSS display width can be useful. Do not automatically double every image: compare the visual result and page weight.
- When a platform publishes exact dimensions or an aspect ratio, follow that current specification. Social networks and marketplaces can crop previews after upload.
A reliable five-step workflow
- Duplicate the original so you always have an untouched master.
- Enter the target width or height and keep aspect ratio locked.
- Choose the output format based on transparency, image content, and destination support.
- Export once, then inspect text, faces, gradients, and edges at the real display size.
- Confirm pixel dimensions and file size in the downloaded result before publishing it.
Choose a format by image type
JPG
Usually the practical choice for photographs. It does not support transparency and loses some information when exported. Lower quality gradually while checking faces, gradients, and high-contrast edges.
PNG
Useful for screenshots, diagrams, logos, and transparent graphics. It is lossless, but photographic PNG files can be much larger than equivalent JPG or WebP files.
WebP
A strong web-delivery option for both photographs and transparent graphics. Check compatibility with the software or service that will receive the file.
What this browser tool can and cannot do
- Processing happens on your device for the core image tools, so practical file and batch limits depend on available browser memory.
- Downscaling removes pixels. Upscaling interpolates new pixels but cannot restore genuine detail or fix an out-of-focus source.
- Changing from JPG to PNG does not restore quality already lost to JPG compression. It only changes how the next file is stored.
- Keep originals for print, archival, legal, or professional work. Treat resized and compressed files as delivery copies.
Detailed guides for the next step
This guide describes the current GetResizer interface and is maintained by the site creator. Last reviewed September 2026. About the project and author.