How to compress an image below 100 KB

Start with the upload requirements

A form that says “maximum 100 KB” is asking about the file's size, not its width or height. Before changing anything, check whether it also requires a particular format or pixel dimensions. A small enough image can still be rejected if it is the wrong format.

Open Compress Image with a 100 KB target, so you do not need to guess a quality setting. You can also open Compress Image on its own, choose Target size and set Maximum file size to 100 KB; the steps below are the same.

Compress your image, step by step

1. Choose or drop your image into the tool. You can add several images if each needs to meet the same limit.
2. Check that Target size is selected and Maximum file size is set to 100 KB.
3. Leave Save as on JPG for a form that accepts JPEG photographs. Use WebP only when the destination explicitly accepts it and your browser supports exporting it.
4. Select Compress to 100 KB. The tool tries different quality settings and can reduce pixel dimensions when quality changes alone are not enough.
5. Download the result and open it before submitting. Check faces, small text and any details the recipient needs to read.

The target uses 100,000 bytes. This avoids the ambiguity between services that interpret a kilobyte as 1,000 bytes and those that use 1,024.

File size and dimensions are different

Pixel dimensions describe how many pixels make up the image. File size describes the space the encoded image takes up. Two images with identical dimensions can have different file sizes: a detailed photograph generally needs more data than a plain background.

For example, a requirement of “600 × 600 pixels, JPG, maximum 100 KB” has three separate conditions. Use Resize Image to set the dimensions, then compress the result. Check the final dimensions afterward because target-size compression may make the image smaller. If all three conditions cannot be met with readable output, check the destination's guidance rather than submitting an unreadable picture.

What happens to quality and transparency?

JPG compression is lossy. Reducing the size can soften detail or introduce visible artifacts, especially around text. Start from the original image each time rather than repeatedly compressing a previously compressed copy.

JPG does not preserve transparency. If your source has a transparent background, inspect the background in the exported image. A destination that requires a transparent PNG needs a different approach; compress it as a PNG with Compress Image, which reduces its colours instead, and review whether the result meets its size limit.

Keep your original. A compressed copy is useful for a form, but it is not a replacement for a full-resolution photo you may want to print or edit later.

If the form still rejects the result

Check the downloaded file's actual size, extension and dimensions. Make sure you selected the new download rather than the original. If a service requires a file strictly smaller than its displayed limit, try a slightly lower target, such as 95 KB.

For smaller limits, start with a 50 KB or 20 KB target. Very small targets can require substantial resizing. The tool reports an error if it cannot reach the requested size.

Where your images are processed

The compressor reads and processes selected images in your browser. Image contents are not uploaded to a LabAnvil processing server. The page still loads website assets, and website analytics or advertising may apply as explained in the privacy policy.

Large images and large batches use device memory. If a batch is slow or fails, try fewer images at a time and keep the page open until processing finishes.