How to compress images inside a PDF

1 min read·25 July 2026

Is your PDF too large? That is almost always because of embedded images. With PDFrust's compressImg tool you shrink images in a PDF without redesigning the document.

Why are PDFs with photos so large?

A camera takes photos of 5–20 MB each. If you embed those uncompressed in a PDF, each image adds up. A 10-page report with 2 photos per page can become 100 MB. The compressImg tool reduces the resolution and JPEG quality of embedded photos.

Setting the quality level

80% quality: barely any visible difference for most readers, file size drops 40–60%. 60% quality: good for digital use, less so for large-format printing. 40% quality: maximum compression, visible degradation when pixel-peeping.

Compress image

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CompressImg vs. compress

CompressImg targets raster images (JPEG, PNG) in the PDF. The compress tool optimises the PDF structure itself (removes duplicate objects, compacts xref tables). Use both for maximum results. Order: compressImg first, then compress.

Privacy and processing

All processing happens locally in your browser — your photos are not uploaded to a server. This is a major advantage over online services that store your files on their servers.