How to Compress Multiple Images at Once
Compressing photos one at a time gets tedious fast when you have a dozen — here's how to batch the whole set to the same target size in one go.
To compress multiple images at once, select all of them together when uploading to an image compressor — most target-size compressors accept multiple files in one drop and process each to the same KB or MB target automatically, instead of you repeating the same steps one photo at a time.
Why this matters for a dossier
A concours or visa application often needs several images prepared to the same or similar limits — an ID photo, scanned pages, supporting documents. Compressing each individually is slow and error-prone (easy to forget which target you set for which file); batching them through the same target-size setting keeps every file consistent.
What to watch for with a batch
- Same target for all, or different targets per file? If your files need different size limits (a photo at 50KB, a document scan at 500KB), run them through separately rather than forcing one target on files with different requirements.
- Check each result, not just that it finished. A batch job can succeed technically while one specific photo still looks worse than the others, if it started from a much higher resolution or had more detail to begin with — spot-check the results rather than assuming uniform quality.
- Keep track of which output is which. Most tools preserve or clearly rename each file, but if you're compressing many similar-looking photos (several ID scans, for instance), double-check the downloaded files match what you expect before using them.
If you have a genuinely large batch
Processing happens locally in your browser, so there's no upload queue or server-side limit to wait on — the practical limit is your own device's memory for very large batches (dozens of high-resolution photos at once), not anything the tool imposes.
Everything runs in your browser — none of your files are uploaded anywhere during compression.