How to Compress an Image to 20 KB, 50 KB or 100 KB (Phone Steps)

To compress an image to 20 KB, 50 KB or 100 KB you re-encode it as a JPEG with fewer bytes: first by lowering the JPEG quality, which is nearly invisible, then by reducing the pixels if quality alone can't get there. A tool that searches for the right quality does this in seconds, and the reduce image size in KB page on IGCOMPRESSOR does it in your phone's browser without uploading anything. This guide explains what the number actually measures, what a photo looks like at each size, how to handle "20 to 50 KB" ranges, and the exact taps on an Android phone.

What "20 KB" actually measures

A kilobyte is 1024 bytes, and a KB limit is about the file on disk, not the picture's dimensions. A photo straight from a phone camera is 3 to 10 MB, which is 3000 to 10,000 KB. A 20 KB limit is less than one percent of that. That is why "just crop it a bit" never works: cropping removes pixels, but the remaining ones are still stored at camera quality.

Two things decide how many bytes a JPEG needs: how many pixels it has, and how precisely the encoder stores them (the quality setting, usually 0 to 100). Halving the width and height cuts the pixels to a quarter. Dropping quality from 95 to 80 roughly halves the bytes at the same pixels, and on a screen you can't tell.

Quality first, pixels second

The order matters. Lower the quality first, because it costs nothing visible until about 60. Only then reduce the pixels, and only as far as the limit forces, because pixels are what make an image look small and soft when a portal displays it.

Here is what fits at the common limits, using the same numbers as the size pages on this site:

These are for normal photos. A signature in black ink on white paper is mostly empty and compresses far better: it can be around 600×200 px and still sit under 20 KB. A photo of foliage or a patterned sari compresses worse and needs fewer pixels for the same limit.

When the form gives a minimum too

Indian portals love ranges: photo 20 to 50 KB, signature 10 to 20 KB. The maximum is easy. The minimum trips people up, because a clean signature or a small photo often compresses to 6 or 8 KB and the portal rejects it as too small.

The fix is padding. The tool adds JPEG comment segments (harmless bytes that every viewer ignores) until the file reaches the minimum. The pixels don't change, the size check passes, and the image looks exactly the same. On the tool, open More options and type the minimum in Min (KB); the result then shows "Between 20 KB and 50 KB" with a tick when padding was applied.

Step by step on an Android phone

There is no app to install. This works in Chrome, and it keeps working if the connection drops halfway.

1. Open reduce image size in KB in Chrome. For a common limit, go straight to the 20 KB, 50 KB or 100 KB page, which opens with the number filled in.
2. Type your limit in the Max file size box and make sure the unit says KB.
3. If the form also gives pixel dimensions, set Resize to Exact size (crop) and type the width and height (for example 200 and 230 for an IBPS photo). If it only gives a KB limit, leave Resize alone; pixels are kept where possible.
4. If there is a minimum, open More options and type it in Min (KB).
5. Tap Choose photos and pick the photo from your gallery, or take one with the camera.
6. Drag the preview to position the crop, then check the size and pixels shown under it. Green means it fits.
7. Tap Download. The file lands in your Downloads folder as a .jpg, ready for the portal's upload button. You can also tap Share to send it into WhatsApp or another app.

The tool tries the highest quality first; if the file is still too big at quality 50, it shrinks the pixels a little and tries again until it finds the largest image that fits, and shows the final size, pixels and quality before you download.

Exact pixels as well as exact KB

Bank and railway forms specify both: 200×230 px at 20 to 50 KB for the photo, 140×60 px at 10 to 20 KB for the signature, and so on. Fill in all three numbers (pixels under Exact size, the maximum in the size box, the minimum in Min (KB)) and the result satisfies all of them at once. Exact size will also enlarge a small image to reach the pixels a form insists on; that can't add real detail, but portals check the numbers, not the sharpness. The dedicated SSC and IBPS / SBI pages have these numbers preset.

Why a file that is the right KB still gets rejected

• Wrong format. The file is a PNG, WebP or iPhone HEIC and the portal wants JPEG only. The tool exports .jpg unless you changed the format under More options.
• Wrong pixels. The size is fine but the dimensions are not what the notification says. Use Exact size.
• Too small. The portal has a minimum and the file is under it. Use Min (KB).
• Rounding. Some portals count 1 KB as 1000 bytes, so a 49.9 KB file can fail a strict 50 KB check. The tool aims a little below the cap for this reason; if you are on the edge, set the limit to 48.
• Photo in the signature slot. It happens. Check the file names before uploading.
• Old file cached. Some portals keep showing the previous upload. Refresh before assuming the new file was rejected.

What this can't do

A 20 KB photo is a 300 to 450 px photo. It looks fine in the box on the form and on a printed admit card, and it looks soft full-screen on a phone. No tool can fit a full-resolution photo into 20 KB, whatever its landing page promises. Keep your original and treat the compressed file as a copy made for one form.

Checklist

• Know all three numbers from the form: maximum KB, minimum KB, pixels
• Crop to the subject before compressing
• JPEG output, not PNG or HEIC, unless the form says otherwise
• Quality first, pixels second; let the tool search
• Use Min (KB) for ranges so the file is never too small
• Check the green size readout, then download
• Keep the original photo

The number on the form stops being a problem once you know which two dials it measures.