How to compress images online without uploading them
Large images slow down forms, email attachments, and websites. FileTools compresses images in your browser, so the files stay on your device instead of being uploaded to a server.
Steps
- Open the image compressor and choose or drop your images.
- Select an output format, quality, and target width.
- Start processing and download the compressed results.
When should you compress an image?
Images used for websites, forms, email, or social posts rarely need the full dimensions of a camera original. Reducing width and quality can make files much smaller while keeping them clear enough for their purpose.
Avatars, thumbnails, and web graphics usually benefit from resizing first. Keep PNG when you need transparency; JPG and WebP are often better for photographs.
Local processing versus uploading
Upload-based services send files to a remote server for processing. Local tools use your browser and reduce network transfer, which is useful for private screenshots, documents, and work materials.
The trade-off is that speed depends on your device and browser memory. Process very large images in smaller batches when needed.
At a glance
Best for: Email attachments, web images, forms, and social posts that have a file-size limit.
Input: JPG, PNG, or WebP images
Output: JPG, PNG, or WebP images with adjustable quality and dimensions
Before downloading
- Keep an untouched copy of the original image.
- Choose the final image dimensions before adjusting quality.
- Inspect text, faces, gradients, and transparent edges after compression.
Why did a PNG become larger after compression?
PNG is lossless and works best for graphics, screenshots, and transparency. A detailed photo may be much smaller as JPG or WebP, while re-encoding a well-optimized PNG can add bytes instead of removing them. FileTools keeps the original when the generated result is not smaller.
What quality setting should I start with?
For photographs, start around 75–85% quality and compare the preview at normal viewing size. Logos, diagrams, and screenshots with small text often need a higher setting or PNG output to keep edges readable.