Are my uploaded images kept private and secure?

Yes! All uploaded and converted files are stored in temporary isolated storage and permanently auto-deleted after 2 hours. We never inspect, sell, or store your private images.

Can I convert iPhone HEIC photos to JPG or PNG?

Yes! Our server-side decoding engine supports Apple HEIC/HEIF photos from iPhone cameras, auto-rotates EXIF orientation, and renders standard universal JPG or PNG files.

What is the advantage of converting PNG or JPG to WebP?

Google WebP offers 25% to 35% smaller file sizes than JPG at equivalent visual quality while supporting transparent alpha channels. Converting your website images to WebP improves Google Core Web Vitals and SEO rankings.

Is there a limit on how many images I can convert?

ConvertHub is 100% free with unlimited single and batch conversions for files up to 25 MB with no registration or credit card required.

ConvertHubPRO / FREE

Top Leaderboard

728 × 90 px • CLS-Locked

Image Converters•Batch (50+ files)

Batch Image Watermarker

Apply text or logo watermarks to 50+ photos simultaneously with customizable opacity, rotation, and position grid in your browser.

Instant browser processing Private & Auto-Purged

Phase 4 Creator SuiteBatch Canvas Engine (50+ Files)

Batch Image Watermarker

Apply customizable text or transparent logo watermarks to 50+ photos simultaneously with 9-point grid positioning, angle rotation, tiled repeat patterns, and instant ZIP download.

100% Private (Browser-Only)

Drag & drop your files here, or browse

Max file size: 50MB (Free Tier)

Upload up to 50+ photos (JPGPNGWebP) to watermark at once

In-Content Native Banner

728 × 90 px • CLS-Locked

How to Convert with Batch Image Watermarker

Follow these 3 simple steps to complete your conversion in seconds.

Step 1 of 3

Upload Your File

Drag and drop your file into the secure dropzone above or click Browse to select from your device.

💡 Tip: Files up to 25MB are completely free.

Step 2 of 3

Choose Conversion Parameters

Adjust target quality, output format, or unit settings as needed.

Step 3 of 3

Get Instant Output & Share

Click download to save your converted file. All files are automatically deleted after 1 hour.

Image Compression & Format Transformation Specification

Formula representation used for accurate calculations:

Output Buffer = Decoded Pixel Array (RGB/RGBA) ↔ Target Quantization Matrix & Huffman/Entropy Encoder Optimization Level: MozJPEG / Deflate 9 / WebP Lossless / Lanczos 3 Resampling

Calculation Example: Uploaded image converted to .jpg with optimized byte stream and stripped EXIF privacy headers.

Image Formats Comparison Reference Matrix

Quick reference lookup table for standard unit calculations.

Comparative technical matrix across modern raster and vector image formats.
Image Format	Transparency & Alpha	Typical Size vs JPG
WebP (.webp)	Full Alpha Support (24/32-bit)	25%–35% Smaller
HEIC (.heic)	Alpha & Depth Map Support	50% Smaller
AVIF (.avif)	Alpha & 12-bit HDR	50% Smaller
JPG / JPEG (.jpg)	No Transparency (Opaque)	Baseline (0%)
PNG (.png)	Lossless True Alpha Channel	200%–400% Larger
GIF (.gif)	1-Bit Binary Transparency	Indexed 256 Colors
SVG (.svg)	Vector Alpha Transparency	Infinite Resolution
ICO (.ico)	32-bit Alpha Multi-Res Favicon	16px to 256px

Frequently Asked Questions

Common questions and answers about Batch Image Watermarker.

ConvertHub leverages high-performance Sharp and MozJPEG rendering pipelines. Our default 85% balanced quality setting maintains high visual fidelity and sharpness while eliminating unnecessary byte overhead.