PNG files eat storage and slow down websites. A single uncompressed PNG screenshot can be 3-5 MB, and if your page has four of those, you’re looking at 15+ MB load times that make visitors bounce.
I’ve been compressing PNGs for web projects since 2019, and I’ve tested pretty much every tool out there. Some are garbage. Some are decent but cap you at 2 files. Here are the ones that actually work, with real compression numbers from the same test files.
Quick Comparison Table
| Tool | Type | Max File Size | Batch Limit | Avg. Reduction | Keeps Transparency | Cost |
|---|---|---|---|---|---|---|
| TinyPNG | Online (lossy) | 5 MB | 20 files | 65-80% | Yes | Free / $39/yr Pro |
| Squoosh | Online (both) | No limit | 1 file | 40-75% | Yes | Free |
| Compressor.io | Online (both) | 10 MB | 1 file | 50-70% | Yes | Free / $5/mo Pro |
| iLoveIMG | Online (lossy) | No limit* | 30 files | 40-60% | Yes | Free / $6/mo Premium |
| Optimizilla | Online (lossy) | No limit | 20 files | 50-70% | Yes | Free |
| FileOptimizer | Desktop (lossless) | No limit | Unlimited | 15-30% | Yes | Free (open source) |
| ShortPixel | Online (both) | 10 MB | 50 files | 50-75% | Yes | 100 free/mo |
*iLoveIMG has no hard file size limit on free tier but throttles speed for large uploads.
If you work with PDFs alongside images, you might also want to check our guide to free PDF editors – several of them handle image optimization inside documents too.
How I Tested These Tools
I ran the same five PNG files through every tool:
- A 4.2 MB screenshot (macOS, 2560×1440)
- A 1.8 MB logo with transparency
- A 6.1 MB digital illustration (complex gradients)
- A 890 KB icon set (flat colors, transparency)
- A 2.3 MB photo saved as PNG
I recorded the output file size, checked for visible quality loss at 100% zoom, and verified that transparency was preserved. All tests done in May 2026.
TinyPNG – Best for Quick Batch Compression
TinyPNG has been the go-to PNG compressor for years, and honestly, it’s still hard to beat for everyday use. Drop your files, wait a few seconds, download the results. Done.
It uses smart lossy compression – specifically, it reduces the number of colors in your PNG using quantization while keeping the alpha transparency channel intact. The results are impressive. My 4.2 MB screenshot went down to 980 KB (77% reduction), and I couldn’t spot the difference without zooming in past 200%.
What works well:
- Drag and drop up to 20 PNGs at once
- Consistently high compression ratios (65-80% on most files)
- Also handles JPEG and WebP
- WordPress plugin available for automatic compression on upload
- API with 500 free compressions/month
What doesn’t:
- 5 MB file size cap on free tier – annoying for large screenshots
- No quality slider. You get what you get
- No lossless option
Look, TinyPNG is the “just works” option. If you need to shrink a handful of PNGs before uploading them to a website, this is where I’d start. The 5 MB limit is the only real friction point.
Squoosh – Best for Manual Quality Control
Squoosh is built by the Google Chrome team, and it takes a completely different approach. Instead of automatic compression, it gives you a side-by-side comparison view where you drag a slider to see exactly what the compression is doing to your image.
You pick the codec (OxiPNG for lossless, or switch to WebP/AVIF for even smaller files), adjust the quality level, and watch the file size update in real time. It’s slower than TinyPNG for batch work, but the control is unmatched.
My 6.1 MB illustration went through OxiPNG lossless at 891 KB reduction (about 15%), or I could switch to lossy with reduced palette and get it down to 1.4 MB (77% reduction) with quality I was happy with.
What works well:
- Real-time before/after comparison with draggable slider
- Multiple output formats: PNG, WebP, AVIF, JPEG XL
- No file size limits, no upload limits
- Works entirely in-browser (your images never leave your device)
- 100% free, no account needed, no ads
What doesn’t:
- One image at a time. No batch processing
- The interface can overwhelm beginners with options
- PWA install is finicky on some browsers
For anyone who cares about image quality – designers, photographers, anyone making assets for a brand – Squoosh is the tool. The privacy angle is a bonus: since it processes locally, your images aren’t uploaded anywhere.
If you also need to resize images for free, Squoosh handles that too in the same interface.
Compressor.io – Best Lossless/Lossy Toggle
Compressor.io does one thing and does it cleanly: compress images with a clear choice between lossy and lossless modes. The interface is minimal – upload, pick your mode, download.
What I appreciate is the honest reporting. After compression, it shows you the exact percentage saved and file sizes. No vague “optimized!” messages. My 1.8 MB logo went to 520 KB in lossy mode (71% reduction) and 1.5 MB in lossless (17% reduction).
What works well:
- Clear lossy vs. lossless toggle
- Supports PNG, JPEG, GIF, SVG, and WebP
- 10 MB file size limit (better than TinyPNG’s 5 MB)
- Shows exact compression stats
What doesn’t:
- One file at a time on free tier
- Pro plan ($5/month) needed for batch processing
- No quality slider in lossy mode
Compressor.io is solid middle ground. Not as automated as TinyPNG, not as detailed as Squoosh. If you want a quick lossy-or-lossless decision without adjusting 12 parameters, this is your pick.
iLoveIMG – Best for Large Batches
iLoveIMG is part of the iLovePDF family, and it follows the same playbook: a clean web interface that handles one task per page. Their compress tool accepts up to 30 images at once on the free tier, which is more generous than most competitors.
Compression results are decent but not leading. My test files saw 40-60% reduction on average – lower than TinyPNG. The tradeoff is that iLoveIMG is more conservative, so quality loss is minimal even in its default mode.
What works well:
- 30 files per batch on free tier
- Google Drive and Dropbox integration for direct import
- Download as ZIP when compressing multiple files
- Also offers crop, resize, watermark, and format conversion
What doesn’t:
- Lower compression ratios compared to TinyPNG
- No lossless option
- Free tier shows ads and limits processing speed
- Premium is $6/month for unlimited processing
I’d use iLoveIMG when I have 15-20 PNGs that need quick compression and the result doesn’t need to be pixel-perfect. It’s fast, handles batches well, and the ZIP download saves time. For related document work, their sister tool offers solid PDF editing too.
Optimizilla – Best No-Signup Batch Tool
Optimizilla is bare-bones in the best way. No account, no signup, no cookie banners. Upload up to 20 images, drag the quality slider for each one, download. That’s it.
Here’s the thing that sets it apart: after compression, each image gets its own quality slider with a before/after preview. So you can dial back the compression on images that look bad and push it harder on images that can take it. Per-image control with batch upload – not many tools do this.
What works well:
- Per-image quality slider with preview
- 20 files per batch, no account needed
- Combined download as ZIP
- Works with PNG and JPEG
What doesn’t:
- Interface looks dated (hasn’t changed in years)
- No lossless compression option
- Only PNG and JPEG – no WebP, AVIF, or SVG
- No API for automation
My 4.2 MB screenshot at quality 70 went down to 1.1 MB (74% reduction). Bumping quality to 90 gave me 2.1 MB (50% reduction). That kind of control per file is genuinely useful when you’re optimizing a mix of screenshots and illustrations.
FileOptimizer – Best Desktop Tool (Lossless)
If you compress PNGs regularly and want to skip the upload-download cycle, FileOptimizer is a Windows desktop app that handles it locally. It’s open source, wraps several optimization engines (OptiPNG, PNGout, AdvPNG, and others), and runs them in sequence for maximum lossless compression.
Lossless means the output is bit-for-bit identical in appearance. No quality loss, period. The tradeoff is smaller reduction – typically 15-30% instead of the 60-80% lossy tools achieve.
What works well:
- True lossless compression with multiple engines
- Unlimited batch size – drag entire folders
- Supports 400+ file formats beyond PNG
- Completely offline, no uploads
- Free and open source (GPL)
What doesn’t:
- Windows only (Linux users can try OptiPNG directly via command line)
- Compression is slow (runs multiple tools sequentially)
- No lossy option
- UI is functional but ugly
My 890 KB icon set went to 620 KB (30% reduction) with FileOptimizer vs. 280 KB with TinyPNG’s lossy. For web performance, that gap matters. But for archival, design files, or anything where quality is non-negotiable, lossless is the way.
ShortPixel – Best for WordPress Users
ShortPixel started as a WordPress plugin and it shows – the web tool is good, but the real value is the automated compression pipeline for WordPress sites. Upload a PNG to your media library, and ShortPixel compresses it in the background.
The free tier gives you 100 image credits per month. Each credit covers one image, including thumbnails. So if WordPress generates 4 thumbnail sizes per upload, one photo uses 5 credits. That’s 20 original images per month on the free plan.
What works well:
- Three compression levels: lossy, glossy (balanced), lossless
- WordPress plugin with automatic background compression
- WebP and AVIF conversion built in
- API available for custom integrations
- Bulk optimization for existing media libraries
What doesn’t:
- 100 free credits/month disappear fast with WordPress thumbnails
- Web tool limited to 50 files per batch
- Paid plans start at $3.99/month for 7,500 credits
- Compression results are good, not best-in-class
My test files averaged 55-65% reduction on lossy, 20-25% on lossless. Those numbers are middle-of-the-pack, but the WordPress integration is the selling point. If you’re running a WordPress site and need set-it-and-forget-it compression, ShortPixel + the free tier is a solid start.
Lossy vs. Lossless PNG Compression: When to Use Which
This trips people up, so let me make it simple.
Lossy compression permanently removes data from the image. For PNGs, this usually means reducing the color palette from millions of colors to 256 or fewer. The file gets dramatically smaller (50-80%), and for most web use cases, the quality difference is invisible. Use this for website images, social media, blog posts, and email graphics.
Lossless compression reorganizes the data more efficiently without removing anything. The file gets somewhat smaller (10-30%), and the output is pixel-identical to the original. Use this for logos, icons, design source files, screenshots with readable text, and anything you might need to edit later.
Not gonna lie, I use lossy compression for about 90% of my work. The size savings are just too significant to ignore, and the quality difference at normal viewing sizes is negligible. But I keep lossless originals in my archive.
Already compressed your JPG files? PNG compression works differently – JPG uses DCT-based compression while PNG uses DEFLATE – so the tools and results aren’t directly comparable.
Tips for Better PNG Compression Results
Start with the right format
If your image is a photo with no transparency, save it as JPG instead of PNG. You’ll get 80-90% smaller files before any compression tool touches it. PNG is for graphics, screenshots, logos, and anything needing transparency.
Reduce canvas size first
Compressing a 4000×3000 PNG and then displaying it at 800×600 on your website is wasteful. Resize the image to the display size before compressing. You’ll get far better results.
Remove metadata
PNG files can carry chunks of metadata: color profiles, creation dates, software info, text comments. Stripping this metadata (most tools do it automatically) can save 10-50 KB per file.
Consider WebP as an alternative
WebP gets you 25-35% smaller files than optimized PNG with the same quality. All modern browsers support it. If you’re compressing PNGs for a website, converting to WebP might be a better move. Squoosh makes this comparison easy.
Frequently Asked Questions
Does compressing PNG reduce quality?
It depends on the compression type. Lossless compression keeps every pixel identical – zero quality loss. Lossy compression (like TinyPNG uses) reduces the color palette, which can drop file size by 60-80% with changes most people can’t see. For photos, lossy is fine. For pixel art, icons, or screenshots with text, stick with lossless.
Is TinyPNG really free?
Yes, the web version is free for files up to 5 MB each, with a limit of 20 images per batch. The API gives you 500 free compressions per month. If you need more, the Pro plan starts at $39/year.
What is the best free PNG compressor?
TinyPNG is the most popular choice for quick lossy compression – it consistently hits 60-80% reduction. If you want full control over quality vs. size, Google’s Squoosh lets you compare before/after side by side with adjustable settings. For batch processing without limits, FileOptimizer is the best desktop option.
Can I compress PNG without losing transparency?
Yes. All the tools in this guide preserve PNG transparency (alpha channel) during compression. This is one reason PNG compression is different from converting to JPG – JPG doesn’t support transparency at all. Both lossy and lossless PNG compression keep your transparent backgrounds intact.
How much can I reduce PNG file size?
Typical results: lossy compression reduces PNG files by 50-80%, while lossless compression achieves 10-30% reduction. The actual savings depend heavily on the image content – screenshots and graphics with flat colors compress much better than photographs saved as PNG.