Why compress an image?
Modern phone cameras produce photos between 2 MB and 8 MB. That is great for printing, but far more than most situations need. Large images are slow to upload, fill up email attachments, and are often rejected outright by online application forms that cap uploads at 20 KB, 50 KB or 100 KB.
Compression removes detail your eyes don't notice (subtle colour variations, sensor noise, invisible metadata), so the file becomes dramatically smaller while the picture looks the same on screen. A typical 4 MB phone photo can usually be brought down to 200–400 KB with no visible difference, and to under 100 KB with only minor softening.
- Online forms and portals: job applications, university admissions, exam registrations and visa portals often set strict size limits.
- Websites and blogs: smaller images load faster, which improves Core Web Vitals and search rankings.
- Email and messaging: stay under attachment limits and send photos faster on slow connections.
- Storage: keep large photo collections without running out of space.
Quality mode vs. target size mode
Quality mode is best when you simply want a lighter file. Around 75–80% quality is the sweet spot for photos: the size drops a lot and the image still looks crisp. Go lower if you need maximum savings and can accept some softness.
Target size mode is built for upload limits. Enter the maximum size in KB and the compressor searches for the best quality that fits. If the limit is very small, for example 10 KB for a large photo, it will also reduce the pixel dimensions slightly, because no amount of quality reduction alone can squeeze a 12-megapixel photo into 10 KB without turning it into blocks.
Typical results for a 12 MP phone photo (4 MB)
| Target | What to expect |
|---|---|
| 500 KB | Visually identical to the original at full resolution |
| 200 KB | Excellent for websites, email and most forms |
| 100 KB | Very good on screen; dimensions may be reduced a little |
| 50 KB | Good for ID-style photos and thumbnails |
| 20 KB | Fine for small passport-style photos on forms |
Which format should you choose?
Leave Output format on Same as original unless you have a reason to change it. If you do:
- JPG: the safest choice for photos and for any form that asks for “JPEG/JPG”. Doesn't support transparency.
- WebP: typically 25–35% smaller than JPG at the same visual quality and supported by all modern browsers. Ideal for websites.
- PNG: best for logos, screenshots, text and graphics with transparency. Photos saved as PNG stay large, so convert them to JPG instead.
Need a different format altogether? Use the Image Converter. It also opens iPhone HEIC photos.
Is it safe to compress images online?
Most online compressors upload your photos to their servers, process them there and send them back. That means a copy of your passport scan, ID card or personal photo sits on someone else's computer, at least for a while.
UploadWell works differently. The compression code is downloaded to your browser along with the page, and your images are processed right there on your phone or computer. Nothing is sent anywhere, which is also why it's fast: there is no upload or download wait. You can check this yourself in your browser's developer tools (Network tab): your images never appear in any request.
Tips for the best results
- Crop away anything you don't need first: fewer pixels means a smaller file at the same quality. The Image Resizer can set exact dimensions.
- For forms that specify both pixel dimensions and KB (for example 200 × 230 px under 50 KB), resize to the required dimensions first, then compress.
- Avoid compressing the same JPG again and again. Always start from the original photo for the best quality.
- For signatures, use the dedicated Signature Resizer, which also cleans up the background.