Lightning-fast batch processing
Process hundreds of images at once using your device’s full power — convert, resize, and watermark without upload delays.
Private by design - HEIC decode included
The fastest way to resize, convert, watermark, and optimise images — right in your browser.
iStrx lets you batch-convert, resize, and watermark hundreds of photos instantly — no uploads, no waiting. Add text or logo watermarks, rename, and export images in modern formats like WebP and HEIC, all securely in your browser.
⚡ 100%
browser-based — no uploads, no privacy risk.
🚀 Up to 4×
faster than online converters.
⏱ Convert 200+
HEIC images to WebP in under 30 seconds — with optional watermarking.
Everything you need to ship assets at speed.
Built for photographers, designers, and teams who live in bulk workflows. istrx blends HEIC support, multi-format exports, and offline-first safety into one polished surface.
Private by design
iStrx never uploads your files. Everything — conversion, resizing, and watermarking — runs locally in your browser for complete privacy.
Smart presets for resizing & watermarking
Quickly resize, compress, convert to WebP/PNG/JPEG, and apply text or logo watermarks using reusable presets.
Batch rename made easy
Automatically rename or organise images for client delivery — perfect alongside watermarking.
Instant download & sharing
Export final images in seconds. Download a ZIP or save directly to your workflow — watermarking included when enabled.
Install & run offline
Add iStrx to your desktop or mobile home screen and use it offline. Your images and watermarks stay on your device.
From upload to download in three simple steps
01
Drop or paste your images
Drag & drop your photos or paste them directly — HEIC, JPG, PNG, and WebP all supported.
02
Choose your output
Resize, compress, or convert formats in bulk. Optionally add a text or logo watermark (position, size, angle). Set filenames and quality levels in seconds.
03
Process & download
Click “Start” to instantly generate your optimised images. Save them directly to your device. Watermarking and conversions apply to every selected file.
Creative teams love the calm efficiency of istrx.
"We converted a full HEIC shoot to web-ready WebP in under a minute. iStrx saved our launch day when the client needed optimised assets fast — even with watermarks."- Maya Chen, Lead Designer at Pixel Camp
Answers before you even ask.
Common questions about image conversion, resizing, watermarking, and privacy
Do my images ever leave my device?
No. Everything runs in the browser. Workers process in-memory and the service worker only caches the app shell.
Can I keep my original filenames, for SEO or client delivery?
Yes. Batch rename is off by default. When you enable it, patterns
like shot-{counter:000} keep extensions aligned with
your chosen format.
What browsers are supported?
istrx targets modern Chromium, Firefox, and Safari. HEIC decode relies on WASM, so make sure WebAssembly is available.
Can iStrx convert HEIC to JPEG, PNG, or WebP?
Yes. You can batch convert between all major formats, including HEIC → JPEG, PNG, or WebP instantly.
Ready to speed up your image workflow?
Convert, resize, and watermark hundreds of images instantly — all offline, private, and free.