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Quick answer
To resize an image to 20KB, open Resize Image, choose Pixels, set a small size (around 300 pixels wide for a signature or 200 × 200 for a photo), pick JPG and click Resize image. Check the size shown, and go slightly smaller if it is still over 20KB.
How to resize an image to 20KB in 3 steps
Add your image
Open Resize Image and drop in a JPG, PNG or WebP. Your phone's camera roll works too.
Set a smaller size
Choose Pixels and enter a width around 300 pixels, with JPG as the format. Fewer pixels is the surest way to hit a small KB target.
Check the size and download
The new file size is shown. If it is under 20KB, download it. If not, go a little smaller or use the File size option on Extreme.
What size in pixels gives about 20KB?
File size depends on the pixels and on how busy the picture is. A plain background compresses far better than a detailed scene. As a rough guide for JPG photos:
Swipe to compare →
| Dimensions | Typical JPG size | Good for |
|---|---|---|
| 300 × 100 (signature) | 5–15 KB | Signed-name uploads |
| 200 × 200 | 10–20 KB | Small ID photo |
| 300 × 300 | 15–35 KB | Profile thumbnail |
If the image is still over 20KB
- Reduce the width a little more (by 10–20%) and resize again.
- Switch to File size and choose Extreme to shrink the file without changing the dimensions.
- Crop away empty background first. Less picture means a smaller file.
- Make sure the output is JPG, not PNG.
Take a photo that fits in 20KB
20KB is right for a signature or a very small photo. The photo itself makes a big difference to the final size:
- Background: dark ink on plain white paper, cropped tight. Plain areas compress far better than busy ones.
- Lighting: even light avoids grainy shadows, which add to the file size.
- Size: under 300 pixels wide is usually enough for this target.
- Crop first: remove anything outside what the form needs to see.
How to check an image's size in KB
- iPhone: in Photos, open the picture and swipe up, or tap the i button, to see its size. In Files, touch and hold and choose Get Info.
- Android: in Google Photos, open the picture and swipe up for details.
- Mac: select the file in Finder and press Command-I.
- Windows: right-click the file and choose Properties.
Zappy shows the new size on screen after resizing or compressing, so you can confirm it before downloading.
Where you'll need a 20KB image
- Signature uploads on online forms and e-applications.
- Tiny thumbnail photos on older portals.
- Forum avatars and email signatures.
Frequently asked questions
How do I resize an image to 20KB for free?
Open Zappy Resize Image, set a smaller width in pixels (around 300 pixels) with JPG output, and check the file size shown before downloading.
Will my photo look blurry at 20KB?
Not if you shrink the dimensions rather than squeezing a large image. A smaller, sharp image looks better than a large, heavily compressed one.
How do I make a signature image 20KB?
Sign in dark ink on white paper, photograph it in good light, crop tightly around the signature, then resize to about 300 pixels wide as JPG.
Can a 20KB image still look clear?
For a signature or a small thumbnail, yes. For a detailed photo, 20KB is very tight, so keep the image small in pixels.
Why is my PNG signature still too big?
PNG files store every detail without compression. Save the signature as JPG, or make it smaller in pixels.
Does it work on iPhone and Android?
Yes. Open Resize Image in Safari or Chrome and pick the photo from your camera roll.
Is my photo uploaded?
No. Resizing happens in your browser, so the photo stays on your device.