Free Image Compressor, Resizer & Converter
KnowAndAskâs Free Image Compressor, Resizer & Converter is an online tool that reduces image file size, changes image dimensions and converts between JPEG, PNG and WebP. Everything runs inside your browser, so your photos are never uploaded to a server.
JPG, PNG, WebP, GIF or BMP
Choose imageSettings
Compare before & download
Drag the slider left or right to compare the original with your result.
Compress, resize and convert images online
How to compress, resize and convert an image
- Upload your JPEG, PNG, WebP, GIF or BMP image.
- Choose the output format and set the compression quality.
- Enter a new width and height, or pick a percentage, to resize.
- Drag the comparison slider to check the result against the original.
- Click Download image.
Large images slow down websites, fill up inboxes and eat storage. This tool reduces file size while keeping the picture looking sharp, and lets you pick the right size and format for the job, whether it is a blog banner, a product photo, a social post or an email attachment.
Which image format should you choose?
| Format | Best for | Transparency | Compression |
|---|---|---|---|
| JPEG | Photos, gradients | No | Lossy, small files |
| PNG | Logos, screenshots, graphics | Yes | Lossless, larger files |
| WebP | Websites, almost everything | Yes | Lossy or lossless, smallest |
How to reduce image size without losing quality
A quality of 70 to 85 percent usually looks identical to the original on screen while cutting the file size dramatically. Resizing to the display size is often the biggest saving: a 4000 pixel wide photo shown at 800 pixels wastes most of its bytes. Use WebP for web pages, JPEG when you need the widest compatibility, and PNG only when you need sharp edges or transparency.
Common uses of an image compressor, resizer and converter
Faster page loads and better Core Web Vitals, smaller email attachments, meeting upload limits on forms and job portals, preparing thumbnails, and converting HEIC-style phone photos exported as PNG into compact JPEG or WebP files.
Frequently asked questions
How do I compress an image online for free?
Upload your image, choose WebP or JPEG as the output format, adjust the quality slider, check the before and after comparison, then click Download. The tool is free and needs no sign-up.
Are my images uploaded to a server?
No. Compression, resizing and conversion happen locally in your browser, so your files never leave your device.
Does compressing an image reduce its quality?
JPEG and WebP use lossy compression, so lower quality settings remove some detail. At 70 to 85 percent the difference is usually hard to see. Use the comparison slider to check before downloading.
Which image format is best: JPEG, PNG or WebP?
WebP gives the smallest files for most web images and supports transparency. JPEG is best for photos when you need maximum compatibility. PNG is best for logos, screenshots and graphics that need sharp edges or transparency.
How do I resize an image without losing quality?
Enter the new width or height with Keep aspect ratio turned on, or use a percentage preset. Reducing dimensions keeps the picture sharp at its new size, and the quality slider controls the extra compression.
Why does the PNG quality slider do nothing?
PNG is lossless, so it has no quality setting. To shrink a PNG, reduce its dimensions or convert it to WebP or JPEG.
What happens to transparent backgrounds when converting to JPEG?
JPEG does not support transparency, so transparent areas are filled with white. Choose PNG or WebP to keep transparency.
Is there a file size limit?
There is no fixed limit, but very large images depend on your device memory and may process slowly.
Is the Free Image Compressor, Resizer & Converter really free?
Yes. It is completely free to use, with no watermark, no sign-up and no limit on the number of images.