Compress an image to 30 KB — a clear small photo without guesswork

How to use Compress Image to 30 KB

1. Choose the image you want to shrink. Several files can go in one batch.
2. Keep Target size at 30 KB, or type the exact figure from your form.
3. Pick Save as: JPEG for anything official, WebP for your own site, or Same format as the original.
4. Decide on Allow resizing if quality alone cannot reach the target. It is on by default.
5. Press Compress to 30 KB and check the result line under each file.
6. Download the -30kb copies.

What it does and when to use it

Thirty kilobytes is a comfortable size for a small picture. It is roughly three times the budget of the strictest signature limits, so a face or a logo keeps its edges instead of turning into blocks.

Good uses:

• Forms with a “30 KB maximum”, or a window like 20–50 KB where you want to stay away from both ends.
• Profile pictures and avatars for forums, chat apps or a staff directory, where a light file loads quickly.
• Email signature images, such as a small logo, so every message you send stays small.
• Thumbnails on a simple website or a slide deck that already has many images.

How it works

Everything runs in a worker inside your browser, so the image is never sent anywhere.

For JPEG output the encoder is MozJPEG, which squeezes more out of each byte than a basic encoder. The tool searches like this:

1. Try full size at top quality. Done if it is at most 30 × 1,024 = 30,720 bytes.
2. Otherwise check 30% quality. If it fits, search upwards for the best quality that still fits.
3. If 30% is too big and resizing is allowed, search for the largest scale that fits, then re-check the quality at that scale.

You get the highest quality at the largest size that fits. If you chose Same format and your file is already under 30 KB, it is passed through untouched.

Worked examples

The bits-per-pixel sum: 30 KB × 8,192 = 245,760 bits, shared between all the pixels.

A 300 × 400 px portrait. 120,000 pixels, so about 2 bits each. That is a healthy budget for a head-and-shoulders photo on a plain background, and the tool will often keep the original size.

A 600 × 800 px photo. 480,000 pixels, about 0.5 bits each. Here the tool may hold the size by lowering quality, or shrink it if that is not enough. The result line says which.

A 256 × 256 px logo saved as PNG. With Same format, the PNG can only get smaller by losing pixels. Switching Save as to JPEG or WebP usually keeps the logo at full size, as long as you do not need transparency.

Limits and tips

• Faces need pixels. For an ID photo, crop to the head and shoulders with the Image Cropper before compressing. A tight crop puts the bytes where they matter.
• Transparent logos. JPEG cannot keep transparency; transparent parts become white. Use WebP if you need both a small file and transparency.
• Batches share one target. Every file in the run aims for the same size.
• Watch for a minimum. If the form says 20–50 KB, a file of 18 KB is not acceptable. Resize Image in KB and Pixels handles a minimum as well.
• Other sizes: Compress Image to 20 KB for tighter limits, Compress Image to 50 KB when you have more room.