How to use the Image Compressor
- Click the upload box and select a JPG, PNG, or WebP image.
- Drag the slider to balance file size against visual quality.
- Download the compressed image once you're happy with the result.
- Use the Copy or Share buttons to save or send your result.
Tip: Start around 80% quality and adjust from there — most photos look nearly identical at 70-85% while shrinking noticeably compared to the original.
Common mistakes to avoid
- Setting quality too low and introducing visible blockiness, especially in photos with fine detail.
- Compressing an already heavily-compressed JPG expecting further dramatic savings.
- Not checking the preview at very low quality settings before downloading.
How Image Compression Works
Quality vs. file size, live
This tool draws your uploaded image onto an HTML canvas, then re-exports it as a JPG at the quality level you choose using the browser's built-in canvas.toBlob() function. Lower quality values discard more visual detail in exchange for a smaller file, while higher values keep more detail at a larger size — you see the exact resulting file size update live as you move the slider.
When to use this tool
Use it to shrink photos before uploading to a website, reduce attachment size for email, or prepare images for faster page loading.
✓ Pros
- Works instantly, right in your browser
- Updates the compressed file size live as you adjust the quality slider
- No sign-up, no ads blocking the result
✕ Limitations
- Output is always JPG, so transparency in PNG or WebP source images is filled with white before compressing.
- Very high-resolution images may take a moment to process on lower-powered devices.
- It compresses one image at a time — there's no batch/multi-file mode.
Choosing a Quality Level
Finding the sweet spot
There's no single right answer — the best quality setting depends on what the image is for and how closely people will look at it.
General quality guidelines
- 90-100%: visually near-lossless, largest file size — good for print or archival.
- 70-85%: a strong balance for most web and email uses; hard to tell from the original at normal viewing sizes.
- 40-65%: noticeably smaller, with some visible softening — fine for thumbnails or where size matters most.
- Below 40%: visible quality loss becomes common — use only when file size is the top priority.
Compression vs. Resizing
Compression and resizing both shrink file size, but in different ways. Compression (what this tool does) keeps the image's original dimensions and reduces file size by discarding fine visual detail. Resizing instead keeps full visual quality but reduces the actual pixel dimensions, which also shrinks file size. For the biggest possible reduction, you can do both — resize first with TickmarkTools' Image Resizer, then compress the result here.
Quick Reference: Quality Settings
A general guide to what each quality range is best suited for:
| Quality | Typical result | Best for |
|---|---|---|
90-100% | Minimal visible loss | Print, archival, professional photography |
70-85% | Balanced size and quality | Websites, email attachments, general sharing |
40-65% | Noticeably smaller | Thumbnails, previews, low-bandwidth contexts |
Below 40% | Visible quality loss | Only when file size is the top priority |
Always preview the result before downloading, since the ideal setting varies by image content.
Features
Live quality preview
Files never uploaded
No data stored
Mobile friendly
How TickmarkTools compares
An honest, feature-by-feature look at browser-based image tools.
| Feature | TickmarkTools | Typical free sites | Premium suites |
|---|---|---|---|
| Price | Free | Free / freemium | Free tier + paid plans |
| Sign-up required | No | Often yes | Yes |
| Data leaves your device | Never | Usually | Usually |
| Watermark on export | None | Sometimes | On free tier |
| Mobile friendly | ✓ | Varies | ✓ |
| Works without account | ✓ | Varies | ✗ |
These are general, illustrative observations about common patterns across free online calculator tools as a category — not verified or benchmarked data about any specific named competitor or product. Individual sites vary and may differ from what's shown here.
Why you can trust this tool
No data stored
Your input is never saved or logged.
Secure processing
All processing happens client-side in your browser.
Fast processing
Results render in milliseconds, no waiting.
Mobile friendly
Use this tool from any device.
No sign-up
No account, no email, no watermark.
Works offline*
Once loaded, this tool needs no internet connection.
Accuracy & limitations
This tool compresses accurately, but it's worth knowing the boundaries:
- JPG output only. Transparent PNG or WebP images will have transparency filled with white in the compressed output.
- Single image at a time. There's no batch mode for compressing multiple files in one pass.
- Performance depends on device. Very high-resolution images may take a moment to process on lower-powered devices.
Image Compressor FAQ
Yes, the Image Compressor is completely free with no sign-up required.
No — compression happens entirely in your browser using client-side technology; your images never leave your device.
70-85% is a strong general-purpose balance; go higher for print or archival use, lower for thumbnails or when size matters most.
The output is always JPG, which doesn't support transparency, so transparent areas are filled with white.
Not currently — this tool processes one image at a time.
No. All calculations run entirely in your browser, and nothing you enter is ever sent to a server or stored.
💡 Quick Help
Tap a common question below for an instant, pre-written answer. This is a deterministic help widget, not a live AI assistant.
Can't find the tool you need?
Tell us what to build next — we ship new tools regularly.
Comments are stored locally in this browser only — they are not public and are not visible to other visitors.