Does SlapMyWeb upload my images?

No. SlapMyWeb processes selected images locally in your browser. The image files are not sent to our server.

Can I compress multiple images at once?

Yes. Add several images to the queue, choose one set of compression settings, and process them as a batch. You can download each result or download the batch.

Does a smaller quality value always make a smaller file?

Usually for JPEG, WebP, and AVIF, but the exact output depends on image content and browser encoding. The tool reports whether each finished file is smaller or larger.

Can I set quality for PNG?

No. PNG is a lossless format and the browser Canvas API does not apply the quality slider to PNG. Choose WebP or JPEG if you want lossy quality control.

Will image dimensions change?

Dimensions stay the same unless you set a maximum width. Images wider than that value are reduced proportionally; smaller images are not upscaled.

What happens to transparency?

PNG and WebP can retain transparency. JPEG does not support transparency, so transparent pixels are filled with white.

Is AVIF output available in every browser?

No. AVIF appears in the format menu only when the current browser confirms that it can encode AVIF images.

Can I compress an animated GIF?

The browser canvas exports a still image from an animated GIF, not its animation. Choose the animated GIF only if you want to compress its first displayed frame.

Why might a compressed image be larger?

If the original image was already optimized or the selected format is less efficient for its content, the new file can be larger. The results show the exact size difference for each image.

Image Compressor Online — Reduce Size

Add images to compressDrop files here or browse your deviceJPEG · PNG · WebP · AVIF · GIF · processed locally

Compression settings

Preview a single image; these settings apply to the whole queue.

Quality80%

Smaller fileHigher quality

Maximum width (optional)

Images wider than this are reduced proportionally. Smaller images are not enlarged.

Output format

The browser encodes this format locally; transparency is retained where supported.

Images stay in your browser; nothing is sent to our server.

What this tool does

Preview output quality before processing
Compare original and compressed file sizes
Batch JPEG, PNG, WebP, and supported AVIF files
Adjust quality and optional maximum width
Your images stay on your device

The short version

What is Image Compressor?

SlapMyWeb's free image compressor reduces image file size in your browser and previews the output before you process it.

Add JPEG, PNG, WebP, or a browser-supported AVIF image, choose an output format, adjust quality and optional maximum width, then compress one image or a batch. Review the actual output size and dimensions before downloading. Your image files stay on your device.

Step by step

How to use Image Compressor

1
Add one or more images
Drop image files into the workspace or browse your device. The first queued image appears in the live before-and-after preview.
2
Choose compression settings
Adjust quality, choose an output format, and optionally set a maximum width. The preview updates to show the first image with those settings.
3
Compress and review the results
Compress the queue, compare actual input and output sizes, then download individual files or the full batch.

What's inside

Everything this tool
does for you

Live before-and-after preview for the first queued image
Batch compression with individual file sizes and dimensions
Choose WebP, JPEG, PNG, or AVIF when the browser supports encoding it
Adjust lossy output quality; PNG stays lossless
Optionally reduce maximum width while preserving proportions
Local browser processing with no image upload to SlapMyWeb

Understand the result

Related free tools

All Image tools

Image Resizer

Resize images to exact pixel dimensions with aspect ratio lock and common size presets.

Image

Image to Base64

Convert any image to Base64 string or data URI for embedding in HTML, CSS and JSON.

Image

Image Format Converter

Convert PNG, JPEG and WebP in your browser. Preview output quality and compare file sizes; AVIF is shown only when export is supported.

Image

Favicon Generator

Generate all 9 favicon sizes from one image — ICO, Apple Touch, Android PWA icons.

Image

Color Picker from Image

Extract HEX, RGB and HSL colors from any image. Click pixels to build color palettes.

Image

Image Cropper

Crop images with preset ratios — 1:1, 16:9, 4:3, 3:2 and free-form. Pixel-precise controls.

Image

You might also need

PDF CompressorPDF & Documents Image Format ConverterImage Image ResizerImage

Questions

Frequently asked questions

Beyond this tool

See the full picture for your website.

Enter your URL for a free audit across eight scored areas. See prioritised issues and clear next steps in one report.

Run a free website audit

Free to start · No signup required

Image Compressor

Compression settings

What is Image Compressor?

How to use Image Compressor

Add one or more images

Choose compression settings

Compress and review the results

Everything this tooldoes for you

Further reading

Related free tools

Image Resizer

Image to Base64

Image Format Converter

Favicon Generator

Color Picker from Image

Image Cropper

Frequently asked questions

Does SlapMyWeb upload my images?

Can I compress multiple images at once?

Does a smaller quality value always make a smaller file?

Can I set quality for PNG?

Will image dimensions change?

What happens to transparency?

Is AVIF output available in every browser?

Can I compress an animated GIF?

Why might a compressed image be larger?

See the full picture for your website.

Everything this tool
does for you