About Compress Image
Compress Image shrinks JPEG, PNG and WebP files while preserving visual quality. SnapToolz uses adaptive compression to find the smallest size that looks identical to the original. Perfect for emails, forums, social media uploads, and trimming megabytes off product photos.
- No uploads
- Browser-only
- Works offline
- 100% free
How it works
- 1
Drop your images
Add one or many — batch processing is supported. Each file is read locally.
- 2
Pick a quality target
Slide between aggressive and lossless. Optionally cap the long edge for resize-on-compress.
- 3
Download the smaller files
Each result shows the new size and savings percentage. Download individually or as a ZIP.
Quality you can't see vs. bytes you can't afford
Every lossy format trades detail for size, and the useful truth is that the last 10-15% of 'quality' is almost always invisible. A photo at JPEG quality 95 and the same photo at quality 80 look identical on screen, yet the q80 file is routinely half the size. SnapToolz's adaptive mode walks down the quality scale and stops where further loss would start to show — so you get the smallest file that still looks like the original, without guessing a number.
Where it shows: hard edges and flat colour. Screenshots, logos, line art and text pick up visible 'mosquito noise' and colour banding under aggressive JPEG far sooner than a photograph does. For those, keep PNG or switch to WebP, which handles both photographic and flat content well.
Pick the right format before you compress
| Content | Best format | Why |
|---|---|---|
| Photographs | JPEG or WebP | Smooth gradients compress efficiently; no transparency needed |
| Screenshots, UI, text | PNG or WebP | Lossless edges; PNG avoids JPEG artefacts around text |
| Logos / line art | PNG or WebP | Few colours, sharp edges — lossless keeps them crisp |
| Needs transparency | PNG or WebP | JPEG has no alpha channel at all |
| Smallest at equal quality | WebP / AVIF | 25-35% smaller than JPEG for the same perceived quality |
Switch formats with the Convert Image tool; the full trade-off analysis is in the image-format guide linked below.
The mistake that doubles your file size
Most oversized images aren't badly compressed — they're badly sized. A 4000x3000 phone photo shown in a 600 px-wide column is carrying ~40x more pixels than the screen will ever display, and no amount of quality tuning fixes that. Cap the long edge to what you actually show (1600-2000 px is plenty for full-width web images, 1200 px in-article) using the resize-on-compress option or Resize Image first, then compress. Resizing first is the single biggest win for web performance — it routinely beats quality tuning by an order of magnitude.
The second mistake is re-compressing a JPEG over and over (open, edit, save, repeat). JPEG is generational — each save loses a little more — so edit from the original whenever you can and treat the compressed copy as a final export, not a working file.
Where compressed images go next
Hitting a platform limit (a WhatsApp status, a forum's 2 MB cap, a marketplace's photo rules)? Compress to the target, then sanity-check that it still reads cleanly at the size it'll be viewed. Building a PDF from photos? Compress the images first, then assemble with JPG to PDF — that's the difference between a 40 MB and a 6 MB document. For the full decision tree on JPG vs PNG vs WebP vs AVIF, read the 2026 image-format guide.
Related guides
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Why local-first tools are faster, safer, and more dependable
The case for processing your files in the tab you already have open — not on someone else's server.
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JPG vs PNG vs WebP vs AVIF — the 2026 image format decision guide
Four formats, four different strengths, and a lot of wrong defaults out there. Here's which to use for photos, graphics, the web, email, and your phone — with real file-size numbers.
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Resize images for the web without losing quality — practical sizing for every context
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Frequently asked questions about Compress Image
Which formats are supported?
JPEG (.jpg/.jpeg), PNG, and WebP — input and output. The output format defaults to the input but you can change it.
Does compression reduce dimensions?
Only if you enable the ‘limit dimensions’ option. By default SnapToolz keeps the original width and height and just optimises the encoding.
Privacy, offline use, browser support, and pricing questions are answered on the site-wide FAQ.