How to Convert Multiple Images at Once (Batch Image Converter)
You just imported 200 photos from your iPhone and they are all HEIC. Your client sent you a folder of 80 PNG screenshots that need to be WebP for the website. You shot a wedding in RAW and the couple wants JPGs for sharing. Whatever the scenario, you need to convert a large number of images from one format to another without sitting there doing them one by one.
When You Need Batch Conversion
Batch image conversion comes up more often than most people expect:
- iPhone photos (HEIC → JPG): every iPhone photo since iOS 11 is HEIC. Transfer a year of photos to a Windows PC and none of them open without conversion.
- Camera RAW files (CR2/NEF/ARW → JPG): professional and hobbyist photographers shoot RAW for editing flexibility but need JPGs for delivery, sharing, or uploading.
- Web development (PNG/JPG → WebP): modern websites serve WebP images because they are 25-35% smaller at the same quality. Converting an entire image directory saves bandwidth and improves page speed.
- Screenshots (PNG → JPG): screenshots default to PNG on most systems, producing files 3-5x larger than necessary for documentation or sharing.
- Web scraping (WebP → JPG/PNG): images downloaded from websites are increasingly WebP, which some older tools and workflows cannot handle.
Method 1: iFormat Batch Mode (Browser-Based)
The image converter accepts multiple files at once. Select all the images you need to convert, pick the output format, and download the results as a ZIP file.
- How it works: drag and drop your files (or click to select multiple), choose the output format (JPG, PNG, WebP, AVIF, GIF, BMP, TIFF), and click convert. Files are processed in your browser using WebAssembly — nothing is uploaded to a server.
- Best for: 5-100 images. No software to install. Works on any device with a modern browser.
- Limitations: very large batches (500+ files) may slow down depending on your device's memory.
Method 2: Preview on Mac
The Preview app on macOS has a hidden batch export feature that many Mac users never discover.
- Select all the images in Finder.
- Right-click and choose Open With → Preview.
- In Preview, press Command+A to select all images in the sidebar.
- Go to File → Export Selected Images.
- In the dialog, click Options, then choose the output format (JPEG, PNG, TIFF).
- Choose a destination folder and click Choose.
Preview handles dozens of images smoothly but struggles with very large batches (200+), and it supports only a few output formats. No WebP or AVIF support.
Method 3: Command Line (ImageMagick)
For developers and power users, ImageMagick's mogrify command converts entire directories in seconds.
- Convert all PNGs to JPGs:
mogrify -format jpg *.png - Convert to WebP at quality 80:
mogrify -format webp -quality 80 *.jpg - Resize and convert:
mogrify -format jpg -resize 1920x1080 *.png
ImageMagick is available on macOS via
brew install imagemagick, on Ubuntu via apt install imagemagick, and on Windows from the ImageMagick website. It is extremely fast — thousands of images in minutes — and supports every format imaginable.mogrify vs convert
mogrify overwrites files in place (or creates new files if the format changes). convert creates a new output file, leaving the original untouched. For batch conversion where the format changes (PNG to JPG), mogrify creates new .jpg files alongside the .png originals. For in-place operations, be careful — mogrify will overwrite without warning.
Comparison: Which Method Should You Use?
- iFormat (browser): no install, works anywhere, private processing, handles 5-100 files easily. Best for most people doing occasional batch conversions.
- Preview (Mac): no install, built into macOS, but limited format support and slow on large batches. Best for quick Mac-only jobs.
- ImageMagick (command line): fastest option, handles thousands of files, full format support, but requires installation and comfort with the terminal. Best for developers and photographers with regular batch needs.
Common Batch Conversion Scenarios
Wedding photographer (RAW → JPG): A wedding shoot produces 1000-3000 RAW files. After editing selects in Lightroom or Capture One, export the finals as high-quality JPGs (quality 92-95%) for client delivery. For web galleries, export a second set at 2048px wide and quality 80%.
Web developer (PNG → WebP): An e-commerce site has 500 product images in PNG. Convert them all to WebP at quality 80% to cut page load time by 30-40%. Keep the PNG originals as fallbacks for older browsers.
Office worker (HEIC → JPG for email): You took 30 photos on your iPhone and need to email them to a client who uses Windows. Batch convert HEIC to JPG, and the client opens them without issues.
Convert Multiple Images Now
Drag and drop any number of images. Choose your output format. Download as ZIP. Free and private.