How to Use ShortPixel's Online Image Compressor

Before you start

ShortPixel's online image compressor works through a browser, so the actual processing does not use your computer's processor for the main optimization. You need a stable internet connection and a file that is ready to upload. Check the current supported file formats on the tool page before you begin. Also note the original pixel dimensions and aspect ratio if you plan to compare the image after compression; the web compressor cannot be assumed to preserve every property unless the interface says so.

Make a copy of the original file if you want a reversible comparison. Some image types and editing histories contain metadata that may be removed or reduced during compression. Do not upload confidential material unless you have already reviewed ShortPixel's privacy and data handling terms because compressed files may pass through the service.

Step-by-step instructions

These steps describe the browser-based ShortPixel image compression flow. Menu labels and limits can change between versions, so use the current tool page as the source of truth.

Open the ShortPixel online image compressor page in your browser. Select the upload area or drag an image into the marked zone. Choose one file first if you are comparing settings because the result can be easier to verify.

Wait for the upload and processing indicator to finish. Do not close the browser tab while the page shows that an image is still being processed. If the tool asks you to select a compression type, choose the option that matches your priority: a stronger compression type is usually smaller, while a gentler option may preserve more detail.

Download the optimized image when the page provides the result. Keep the original file for review unless you have confirmed elsewhere that your source is expendable. If you need to test several compression levels, repeat the process with the same untouched original rather than re-compressing the downloaded copy repeatedly.

Check the output

Compare the downloaded version with the original at actual viewing size, especially in areas with fine detail, text, skin, hair, or shallow gradients. A useful check is to open both images side by side and look for visible banding, blocky edges, color shifts, or lost details. The file format may differ from the original, and compression can reduce transparency quality, so verify any transparent areas against a contrasting background.

Confirm the result properties separately from how it looks. Inspect the final file size and check whether the pixel dimensions and aspect ratio match your intended use. A smaller file is not automatically suitable for every task, especially when an image needs to remain sharp after later cropping or resizing.

Common problems and next steps

If compression makes a detailed image look soft or patchy, switch to a milder compression setting or use a better-suited starting format. For images containing sharp interface elements or text, a lossless or high-quality export may be more appropriate than aggressive optimization.

If the tool rejects the upload, confirm that the file type and size are within the current limits shown on the page. A valid image that opens locally but fails in the browser may need to be re-exported through your editing app because the file contains unsupported structure or incomplete encoding.

When you need to preserve transparency, compare the transparent region after compression rather than checking only the opaque areas. Some conversions flatten transparency or change the file format in a way that affects later use. If the compressed version does not meet the requirement, return to the original export and adjust the source before running compression again.