JPEG, PNG, WEBP, GIF, BMP, TIFF, SVG, ICO, HEIC, RAW and AVIF — every format has one job it does best. This is the complete decision guide.
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Knowledge Base
Image optimisation,
explained properly
Long-form guides on compression, file formats, quality and web performance — plus a hands-on field guide to every setting in the tool. Written for real people, not just engineers.
In-Depth Guides
Benchmarks
AVIF vs WebP vs JPEG in 2026: The Real Benchmarks
Three modern formats, one honest comparison. Which one to ship, when AVIF is worth the slower encode, and why JPEG XL still isn't ready.
iPhone
HEIC Explained: Why Your iPhone Photos Won't Open (and How to Fix It)
That mysterious .heic file that triggers “unsupported file type” — what it is, why Apple uses it, and the fastest way to make it open anywhere.
Beginner
Image Compression for People Who Just Want Smaller Photos
Phone photos are huge and attachments get rejected. The plain-English guide to shrinking images fast — no jargon, no quality loss you can see.
Fundamentals
Lossy vs Lossless Compression: The Difference That Actually Matters
Two kinds of compression, two completely different jobs. Pick the wrong one and you waste either bytes or quality. Here's how to always pick right.
Deep Dive
What the JPEG Quality Slider Actually Does
Most people think quality 50 means “half the detail.” It doesn't. Understanding what really happens will change how you export every image.
Performance
Your Images Are Probably the Slowest Thing on Your Website
Developers blame JavaScript when a page drags. The real culprit usually sits in the media library. Here's how images wreck speed — and Core Web Vitals.
Sizing
Resize, Don't Just Compress: The Complete Guide to Image Dimensions
Compression gets all the attention, but resizing is the bigger lever. How to choose the right pixel dimensions for the web, email, social, and print.
SEO
Image SEO in 2026: Ranking Higher with Faster Pictures
Search engines reward fast, well-labelled images. A practical checklist for alt text, file names, modern formats, and the Core Web Vitals that move rankings.
Explainer
How Image Compression Actually Works (Without the Math Degree)
Frequency, perception, and redundancy — the three ideas behind every image codec, explained in plain language so the settings finally make sense.
Privacy
Should You Trust Online Image Tools With Your Photos?
Free online compressors are convenient — and they often upload your photos, GPS coordinates and all, to someone else's server. What to check before you do.
Photography
Image Compression for Photographers: Quality Without Compromise
Exporting is where your colour work and fine detail either survive or die. The settings that protect your craft from delivery to print to the web.
Hands-On Tips & Tricks
A practical field guide to every setting in the tool — what each one does, the numbers that matter, and the exact menu path. Filter by what you're working on.
Web#01
Resize Before You Compress
The single biggest win, and most people skip it. A phone photo is often 4,000–8,000px wide, but a website only displays it at 800–1,600px — the rest is downloaded and thrown away.
Resizing the long edge to 1,600px typically cuts the file 70–80% before any quality compression. Do this first, then drop quality, and the savings stack.
Quality#02
Quality 80–85 is the Sweet Spot
The slider isn't a fidelity dial — it controls how aggressively detail is rounded off. Going from 100 to 85 usually shrinks a JPEG 60–75% while staying visually identical.
Export at 80, then zoom to 100% on a detailed area. If there are no blocky artefacts, you've gone low enough.
Web#03
WEBP for Web, JPEG for Email
WEBP is 25–35% smaller than JPEG at the same quality with near-universal browser support — the right default for anything on a website.
The exception is email: some clients (older Outlook) still won't render WEBP, so attach JPEG when you're unsure.
Batch#04
Rename a Whole Batch
Drop a pattern into Batch Rename and every file is renamed in one pass. Use photo_{num} to auto-number or {date} to stamp the date — handy for client deliveries.
You can process up to 10 images at once, so a full set comes out consistently named.
Print#05
Don't Compress for Print
Screens are 72 DPI, so web compression is invisible there. Print is unforgiving: at 300 DPI a compressed JPEG shows artefacts a screen would hide.
For brochures or photo prints, send the full-resolution original (TIFF or JPEG 100) and use compression only for the on-screen proof.
Privacy#06
Strip EXIF Before Sharing
Every photo carries hidden EXIF data: camera model, timestamp, and often exact GPS coordinates. Post it and you may be publishing your home address.
Strip metadata before anything goes public. Keep EXIF only when it's useful and private.
Quality#07
Grayscale Cuts Size by a Third
Colour data takes real space. Converting to grayscale drops roughly a third of a JPEG's size with no loss of meaningful information when colour isn't needed.
Ideal for scanned documents, receipts, and editorial black-and-white. Apply it via the Image Filter dropdown.
Batch#08
Search the Queue Before Deleting
Loaded the maximum 10 images but want to pull just one? Type part of its name into Search Files to isolate it, so you remove the right file instead of clearing everything.
Click any filename in the queue to copy it to your clipboard.
Print#09
Watermark Proofs, Not Finals
Before sending unpaid proofs, add your studio name as a watermark. A semi-transparent label centred on the image deters reuse without ruining the preview.
Set position to Center for maximum coverage, then export clean versions once approved.
Web#10
Optimise the Hero Hardest
The big image at the top of a page loads first and is measured directly by Google's LCP score — the one image where every saved kilobyte improves speed and SEO.
Resize to its real display width, then keep the lowest quality where the difference is invisible.
Quality#11
Fix Orientation On Export
Photos that import sideways usually have a rotated EXIF flag, not rotated pixels. Setting an explicit rotation bakes the correct orientation into the output so it displays right everywhere.
Use the Rotation control to nudge by 90°, 180°, or 270° before exporting.
Privacy#12
Always Keep Your Originals
Compression is a one-way trip. You can make smaller copies from a master, but you can never recover detail from a file you've already crushed.
Everything here runs locally, so your originals never leave your device — but still archive the full-size files before exporting copies.
Format Comparison Guide
Not sure which format to pick? Match the job to the row.
| Format | Best For | Transparency | Animation | Compression | Rel. Size |
|---|---|---|---|---|---|
| AVIFSmallest | Large web/hero images | Lossy / Lossless | Smallest | ||
| WEBPWeb | Web images, PWAs | Lossy / Lossless | Very Small | ||
| JPEGUniversal | Photos, email, print | Lossy | Small | ||
| PNG | Logos, screenshots, UI | Lossless | Medium–Large | ||
| HEIC | iPhone capture (convert to share) | Lossy | Very Small | ||
| GIF | Simple animations, memes | Lossless | Medium | ||
| TIFFPrint | Professional print, archiving | Lossless | Very Large | ||
| SVG | Icons, logos, illustrations | Vector | Tiny | ||
| BMP | Windows legacy, raw editing | None | Very Large | ||
| ICO | Browser favicons | Lossless | Tiny |
Frequently Asked Questions
What is the best image format for the web in 2026?
WEBP is the best all-purpose web format in 2026 — roughly 25–35% smaller than JPEG at the same quality with near-universal browser support. Use AVIF for large hero and product images where you want the smallest possible file, and keep JPEG for email and print.
How do I make my photos smaller without losing quality?
Resize the image to its real display dimensions first, then export as WEBP or JPEG at around quality 80. Resizing alone often cuts file size 70–80%, and quality 80 is visually identical to the original for most photos.
Why won't my iPhone HEIC photos open on Windows or websites?
No major browser supports HEIC natively and Windows needs an extension, mainly due to HEVC licensing. Convert HEIC to JPEG for maximum compatibility or to WEBP/AVIF for the web.
Is it safe to use online image compressors?
Many online tools upload your photo — including its GPS and EXIF metadata — to a server. A tool that processes images locally in your browser never sends the file anywhere, which is the safest option for personal photos.
Does image optimisation help SEO?
Yes. Image size is the biggest factor in Largest Contentful Paint, a confirmed Google ranking signal that should stay under 2.5 seconds. Modern formats, correct dimensions, explicit width/height, and descriptive alt text all improve rankings.