Why photos look blurry after uploading, and how to keep them sharp

The photo looks perfect in your gallery. You post it and it looks smeared, blocky in the sky, or fuzzy around text. Nothing is wrong with your camera. Almost every app and website resizes and recompresses uploads to save storage and data, and some ways of preparing a photo survive that much better than others.

What the apps do

• Resize: a 4,000-pixel photo is scaled down to the app's maximum width. Each network has its own limit; Instagram, for example, works at 1,080 pixels wide for feed posts.
• Recompress: the resized image is saved again as a JPG or similar at the app's chosen quality, often fairly low to keep files small.
• Crop: photos outside the allowed shapes are cut to fit.

Each step loses some detail. A photo that has already been compressed hard before uploading loses more, because the app is compressing the artefacts as well as the picture.

How to keep photos sharp

1. Start from the original, not a copy saved from a chat or a previous post.
2. Upload at the size the app uses. For Instagram, the Instagram Image Resizer outputs exactly 1,080 pixels wide in the right shape, so the app does not need to resize or crop it again.
3. Use high quality when you resize. If you make a smaller version with Resize Image, save it with little compression. Let the app do the only heavy compression.
4. Do not compress twice. If you need a small file for email, make it separately from the copy you post. Compress Image shows a before-and-after preview, so you can see the cost of each quality level.

Messaging apps

Chat apps compress photos more than social networks, because they assume photos are for viewing on a phone. To send a photo at full quality:

• WhatsApp: use the HD option when sending, or send the photo as a document, which keeps it untouched.
• Other messengers: look for “send as file” or “original quality”.
• For printing or archiving, use a file-sharing link or email rather than a chat.

Why some photos suffer more

• Fine detail such as grass, hair, gravel and fabric patterns is the hardest thing to compress and smears first.
• Smooth gradients such as skies and studio backdrops show banding and blocks.
• Small text, for example in a poster or a screenshot, blurs badly when scaled down. Make text larger in the design rather than relying on the app to keep it sharp.
• Night photos already contain noise, which compression turns into blotches.

It might be the photo

Sometimes the original is soft too and only looks sharp because the gallery shows it small. Zoom to 100% before blaming the app. Motion blur, missed focus and a smudged lens all look like compression once the photo is enlarged. For screenshots of documents, PNG survives better than JPG; see JPG vs PNG vs WebP.

For Instagram specifically, see Instagram image sizes and adding white borders to fit a photo.