How image compression actually works
Most photos contain more pixel detail than the human eye can distinguish at normal viewing sizes. Compression algorithms reduce that redundant data — either by simplifying color information (lossy) or repacking the file more efficiently (lossless) — to shrink the file without a noticeable visual difference.
A practical target: aim for 70–85% quality
For most photos on the web, a quality setting between 70% and 85% cuts file size by 50–80% compared to the original, with almost no visible difference at normal zoom levels. Go lower only if file size is critical and some softness is acceptable.
Compress images with Filezons
- Open the Image Converter from the homepage.
- Upload your image(s) — batches are supported.
- Drag the compression/quality slider and watch the estimated file size update live.
- Download the compressed file(s) once you're happy with the balance of size and quality.
Choosing the right format for the job
JPG and WebP compress photos well because they can discard detail the eye barely notices. PNG is lossless, which is why it's the right choice for screenshots, logos, and graphics with sharp text or flat colors — compressing a PNG saves some space but converting a photo-heavy PNG to JPG or WebP usually saves far more.
Compressing for specific platforms
Social media platforms typically re-compress images on upload anyway, so aiming for a moderate quality setting (75–80%) before uploading avoids double-compression artifacts. For email, smaller is generally better since large images slow down loading in the inbox. For your own website, pair compression with proper image dimensions — there's no benefit to serving a 4000px-wide image if it only displays at 800px.
Frequently asked questions
What's the difference between compressing and resizing?
Compression reduces file size by simplifying pixel data at the same dimensions. Resizing shrinks the actual width and height. Combining both gives the smallest possible file.
Will compressed images look pixelated?
Not if you stay within a reasonable quality range (70%+ for JPG/WebP). Extreme compression below 40–50% is where blockiness and artifacts start to appear.
Can I compress PNG files too?
Yes — PNG compression in Filezons uses lossless re-encoding, so file size drops with zero quality loss, though the savings are usually smaller than converting to JPG or WebP.
Can I compress many images at once with the same settings?
Yes — batch compression applies your chosen quality setting consistently across every uploaded image.
Does compressing an image remove its transparency?
Not with PNG or WebP, both of which support transparency after compression. Converting a transparent PNG to JPG will remove transparency, since JPG doesn't support it.