Compress Image to a Target KB
No upload · Runs in your browserQuality comparison
Drag the center handle left and right to compare the original and the result. If you resized, the original is shown at the same size.
How to use
- Drag and drop photos or click to choose them. You can add several at once.
- For an application or passport photo, tap a spec preset; otherwise set a target size (KB) and an output format.
- If needed, set an exact width × height in pixels or a maximum edge length. After changing settings, press ‘Reprocess with current settings’.
- Check the final size, quality and resolution in the results list, inspect the quality with the comparison slider, then download images one by one or as a ZIP.
Frequently asked questions
How does it hit the target file size?
It re-encodes the image several times, binary-searching the JPEG/WebP quality value, and picks the highest quality that stays under the target. If the file is still too large even at 50% quality, it shrinks the resolution step by step and repeats the same search. The result is the sharpest possible file just under your target.
Is 1KB 1000 bytes or 1024 bytes?
Both conventions are in use. Windows Explorer shows 1KB as 1024 bytes, while some websites count 1000 bytes. The default is 1024 bytes; if you don't know which rule the recipient uses, choose ‘1KB = 1000B’. Since that targets the smaller number, the file passes under either rule. Spec presets use 1000 bytes automatically.
Where do the spec preset numbers come from?
We checked each agency's official guidance on September 23, 2026. The Korean national civil service recruitment system requires 137×177 pixels and under 350KB; Korea's Q-Net requires JPG, 200KB or less and at least 300×400 pixels; the Korean Ministry of Foreign Affairs recommends 413×531 pixels and 500KB or less for online passport photos; and the U.S. Department of State DV lottery photo must be a 600×600-pixel JPEG of 240kB or less. Rules can change, so always check the agency's latest notice before submitting.
What happens when I save a transparent PNG as JPEG?
JPEG can't store transparency, so transparent areas are filled with a background color. White is the default, and you can change it in the background color field. If you need to keep transparency, save as WebP.
Can the result be larger than the original?
Yes — re-saving a small, heavily compressed photo at high quality can make it bigger. In target size mode, turn on ‘Keep the original if it's already under the target’ and the original is returned as-is when it's under the target and the format and dimensions are unchanged.
Are my photos sent to a server?
No. Decoding, cropping, resizing and encoding all run on your device using the browser's Canvas feature, and image data is never transmitted anywhere.
Related guides
JPG vs PNG vs WebP vs AVIF — Which Image Format Should You Use?
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ID and Application Photo Size Guide — Korean Passport, ID Card, Driver's License, Civil Service Exam, Q-Net and US Visa
Official photo specs for Korean passports, ID cards, driver's licenses, the civil service exam (137×177px, under 350KB), Q-Net and US visas (600×600px, 240kB).
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