Choose the limit, such as 50 KB or 100 KB, in the image compressor and it finds the best quality that fits. It works on phones and computers, and the photo isn’t uploaded.
Compress an imageThe quick way: pick the limit and compress
- Open the photo in the compressor. Drop it on the box or tap to choose it. Several photos at once is fine.
- Pick the size the form asks for. 20, 50, 100, 200 and 500 KB are one tap each, or type any number. There are also pages set up for 20 KB, 50 KB and 100 KB.
- Check and download. Each file shows its new size and pixel dimensions. Use Compare to look at the result next to the original before you save it.
The compressor lowers the JPEG quality first. Only if that can’t reach the limit does it reduce the width and height as well, keeping the shape. It aims just under the number you pick, so a 50 KB target lands below 50,000 bytes and passes whether the website counts a kilobyte as 1,000 or 1,024 bytes.
What decides the size in KB
Three things set how many kilobytes a photo takes, in this order of importance:
- Pixel count. A 12-megapixel phone photo (4032 × 3024) has about 12.2 million pixels. A form photo of 200 × 230 has 46,000. Fewer pixels is the biggest saving by far.
- Format. JPEG is made for photos and can trade a little quality for a much smaller file. PNG keeps every pixel exactly, so a photo saved as PNG is usually several times bigger. Use JPG for photos and scans unless the form says otherwise.
- Detail. A plain wall or white paper costs almost nothing. Grass, gravel, patterned clothes and noise from a dark room cost a lot, because every speck is detail the file has to describe.
You can see why pixels matter with a little arithmetic. One kilobyte is 8,000 bits, so:
50 KB at 4032 × 3024: 400,000 bits ÷ 12,192,768 pixels ≈ 0.03 bits per pixel
50 KB at 800 × 600: 400,000 bits ÷ 480,000 pixels ≈ 0.83 bits per pixel
The first can only look blocky. The second has enough room for a clean JPEG. The DPI number stored in the file has no effect on its size in KB.
What each size looks like
These are typical results from our compressor on ordinary phone photos. A photo with lots of fine detail ends up a little smaller in pixels; a plain, well-lit one stays larger.
| Limit | Typical width after compressing | Good for |
|---|---|---|
| 20 KB | about 300 to 450 px | Exam and job form photos, signatures |
| 50 KB | about 500 to 700 px on the long side | ID and application photos |
| 100 KB | about 1000 to 1600 px | Portal uploads, document photos |
| 200 KB | about 1600 to 2000 px | Website and listing images |
| 500 KB | often the full 12 MP is kept | Email, chat, slides |
Don’t compress harder than you need to. If the form allows 200 KB, a 190 KB file looks much better than a 20 KB one, and nothing rewards you for going smaller.
When the form gives pixels as well as KB
Recruitment and exam forms often set both. The IBPS notification for its 2026 probationary officer recruitment (CRP PO/MT-XVI, dated 30 June 2026) is a typical example:
| Upload | Pixels (preferred) | File size | Format |
|---|---|---|---|
| Photograph | 200 × 230 | 20 to 50 KB | JPG or JPEG |
| Signature | 140 × 60 | 10 to 20 KB | JPG or JPEG |
| Left thumb impression | 240 × 240 | 20 to 50 KB | JPG or JPEG |
| Handwritten declaration | 800 × 400 | 50 to 100 KB | JPG or JPEG |
Notice the minimums. A 200 × 230 photo can easily come out under 20 KB, which is rejected as too small. When a form gives pixels, crop and set those first with Resize image, then compress to a target inside the range, such as 45 KB for a 20 to 50 KB photo. For signatures, see the signature size guide. If the form gives a size in cm, multiply by the DPI and divide by 2.54 to get pixels.
On an iPhone or Android phone
Neither phone has a built-in setting that saves a photo at a chosen KB size, so use the compressor in your browser. It runs on the phone itself.
- iPhone: open the compressor in Safari, tap the box and choose Photo Library. Safari can read iPhone HEIC photos directly, and the result is saved as a JPG. Tap Download, then find it in the Files app under Downloads.
- Android: open it in Chrome, tap the box and pick the photo from your gallery or files. The compressed JPG goes to the Downloads folder.
A screenshot of a photo is not the same as the photo. It records your screen’s resolution and any interface on top, so start from the original file.
On Windows or Mac, without a website
- Mac, Preview: choose Tools › Adjust Size, tick Resample image and enter a smaller width; Preview shows the resulting size at the bottom of the window before you save. File › Export also has a quality slider for JPEG.
- Windows, Paint: choose Resize, switch to Pixels, keep Maintain aspect ratio ticked and enter the width, then Save as JPEG. Paint has no quality setting, so you may need a few tries at different widths to land under a strict limit.
Both work, but neither aims at a size for you: you resize, save, check the KB and repeat. The browser compressor does that loop automatically.
Keeping it sharp at a small size
Shrinking a file always throws something away. The aim is that nobody can see what went. These help most:
- Crop before compressing. Every pixel of background you remove leaves more bytes for the face or the text.
- Use good light. A photo by a window in daylight has less grain than one under a lamp, and grain is expensive.
- Compress the original once. Compressing an already-compressed JPEG again adds new damage each time.
- Check at 100%. Zoom in on eyes or small print. Blocky squares or smeared edges mean the target is too small for that pixel size; crop tighter or make it a little smaller in pixels.
For the strictest limit of all, the 20 KB photo guide covers converting cm to pixels and the errors forms give.
Sources
- IBPS, Notification CRP PO/MT-XVI (30 June 2026), Annexure III: Guidelines for scanning and upload of documents. Photo, signature, thumb and declaration sizes
- Apple Support: Resize, rotate or flip an image in Preview on Mac. Adjust Size, Resample image and the new size shown