Pixora guide · Updated September 21, 2026
How to Compress Images Online
Learn how to reduce image file size while keeping enough visual quality for the final destination.
Compress images →What this guide covers
This guide focuses on the practical decisions behind image editing: pixel dimensions, file formats, compression settings, browser support and the final destination of the image. The goal is to help you choose a workflow based on the actual requirement rather than simply producing the smallest possible file.
What image compression changes
Compression reduces the amount of data needed to represent an image. The result depends on the image dimensions, visual complexity, chosen format and encoding settings. A photograph with many fine textures may respond differently from a flat illustration or screenshot.
A practical workflow
- Open the Pixora Image Compressor.
- Select one image or a batch. Keep an untouched copy of the originals.
- Start with a moderate quality setting instead of immediately choosing the smallest output.
- If a form has a size limit, enter a target such as 100KB and treat it as a best-effort goal.
- Inspect text, faces, edges and fine detail in the processed preview.
- Download the version that meets both the visual and file-size requirements.
Resize before compressing when dimensions are excessive
A common reason an image remains large is that its pixel dimensions are much greater than its final display area. If a website card only needs a 1000-pixel-wide image, sending a 4000-pixel source can preserve data that the visitor never sees. Resize first when the destination does not need the original dimensions, then compress the resized copy.
Choosing a format
JPG is commonly useful for photographs, PNG is useful when lossless output or transparency matters, and WebP can be efficient for many web images when the destination supports it. Test the actual image rather than assuming one format always produces the smallest file.
Common mistakes
- Compressing the same already-compressed file repeatedly.
- Ignoring the required pixel dimensions and focusing only on KB.
- Replacing the original before checking the output.
- Choosing a format that the destination does not accept.