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How to Batch Convert Hundreds of Images at Once

You have a folder with 200 PNG screenshots. Your CMS only accepts JPEG. Converting them one by one would take all afternoon. There has to be a better way.

There is. Batch conversion lets you process multiple files in one go - same conversion, applied to every file. No repetitive clicking, no waiting between each one.

When you need batch conversion

It comes up more often than you would think:

  • Website migration - converting all images to WebP for better performance
  • Social media - resizing product photos to platform-specific dimensions
  • Photography - converting RAW exports from one format to another
  • Documentation - converting screenshots for a user manual or knowledge base
  • Email marketing - optimizing campaign images to reduce load times

The online approach

Most online converters process one file at a time. But tools that support multi-file upload let you drop up to 20 files at once. PrivConvert supports this - drag a selection of files onto the converter, and they are all processed together. You get a ZIP file with all your converted images.

The advantage: no software to install, works on any device, and your files are processed in memory without being stored.

The limitation: most online tools cap batch sizes at 20-50 files per upload. For larger batches, you would process them in groups.

Picking the right output format

Before you batch convert, make sure you are converting to the right format:

  • JPG - best for photos. Smallest file size, but no transparency. Use 80-85% quality.
  • PNG - best for screenshots, graphics with text, anything needing transparency.
  • WebP - 25-35% smaller than JPEG at the same quality. Ideal for web use.
  • AVIF - even better compression than WebP, but slower to encode.

For most web optimization workflows, converting to WebP is the best move. You get significant file size reduction with broad browser support.

Tips for efficient batch processing

Group by type. Do not mix photos and screenshots in the same batch. Photos work best with lossy compression (JPEG, WebP). Screenshots with text work best with lossless (PNG) or carefully tuned lossy.

Check a sample first. Before converting 500 images, convert 2-3 at different quality settings. Make sure the output looks good before processing the whole batch.

Keep your originals. Always keep the source files until you have verified the converted versions are acceptable. Conversion is a one-way process - you cannot get the original quality back from a compressed file.

Try it

Pick a conversion tool below, select multiple files, and watch them convert in seconds:

Batch convert to WebP