Image Compressor Online Free — Reduce Image File Size

Why Compress Images?

Large image files slow down web pages, fill up email inboxes, and eat through storage on phones and servers. A raw photograph from a modern phone can easily be 5–10 MB. The same image compressed to 80% quality in WebP or JPG format is typically under 500 KB with no visible difference at normal viewing sizes.

For websites, image size is one of the biggest contributors to slow load times. Google PageSpeed and Core Web Vitals both penalise pages with unoptimised images. For personal use, compressed images upload faster to social platforms, attach more easily to emails, and take up less storage.

How to Compress an Image

1. Open the Image Compressor.
2. Click Choose File or drag your image onto the upload zone.
3. Adjust the Quality slider (1–100). Lower = smaller file, more compression.
4. Optionally set a maximum Width or Height to resize as well as compress.
5. The preview updates live — check the estimated file size and visual quality.
6. Click Download when you are satisfied.

Quality Settings Reference

Compression Tips

Start at quality 80 for photos

For most photographs shared on the web or via email, a quality setting of 80 produces output that is visually indistinguishable from the original at typical display sizes. Check the live preview at 100% zoom if you are not sure — compression artefacts appear first in areas with smooth gradients, like blue skies or skin tones.

Resize before sharing on social media

Social platforms resize images anyway, but uploading an oversized image first wastes bandwidth and processing time. Most platforms display images at 1200 px wide or less. Setting a max width of 1200 px in the compressor and using quality 80 gives a file that will look identical on screen to the uncompressed original.

Compress logos and graphics at higher quality

Logos, diagrams, and screenshots with sharp text or hard edges show compression artefacts more readily than photos. Use quality 90+ for these, or consider converting to PNG (lossless) using the Image Converter if the file size difference is acceptable.

Check the savings before downloading

The live preview shows the compressed file size alongside the original. If the saving is less than 20% at your chosen quality, try lowering the quality slider or switching to a more efficient format such as WebP.

Which Image Format Should You Use?

The format you choose affects file size and quality independently of the quality slider. Different formats suit different content types — picking the right one before compressing can halve the file size without touching quality at all.

For new web projects, WebP is the best default: supported in all modern browsers, 25–35% smaller than JPEG at equivalent quality, and supports transparency unlike JPEG. To convert formats before compressing, use the Image Converter.

Frequently Asked Questions

What file size should I aim for on a web page?

Google's PageSpeed guidelines recommend keeping individual images under 200 KB for above-the-fold content and under 500 KB elsewhere. Hero images — large background photos — should ideally be under 300 KB. For pages with many product images, aim for a total image weight under 1.5 MB. The compressor's live file-size readout makes it straightforward to hit these targets.

Does compressing an image reduce its dimensions?

Not unless you set a maximum width or height in the resize fields. Compression reduces file size by discarding colour data and fine detail without changing pixel count. For web use, combining both — quality 80 and a max width of 1200 px — achieves the best balance of size and visual quality.

Can I compress a PNG without losing transparency?

Yes. The compressor preserves the alpha channel in PNG files. If you want a smaller transparent image, convert to WebP first — it supports transparency and compresses significantly smaller than PNG for the same visual output.

Will compressing an image multiple times damage quality?

For lossy formats like JPEG, yes. Each compression pass introduces new artefacts on top of previous ones — a process called generation loss. Always work from the original uncompressed source when you need to edit and re-save. For lossless formats like PNG, repeated compression does not degrade quality.

Privacy: Your Images Never Leave Your Device

All compression happens in your browser using the Canvas API. Your image is read into memory, compressed, and offered for download — it is never sent to a server. This makes the tool safe for personal photos, confidential documents scanned as images, or any image you would prefer not to share with a third-party service.