Компрессор PDF против компрессора изображений: Что нужно?
Quick Answer
Используйте PDF Compressor для .pdf файлов (отчёты, документы). Используйте Image Compressor для файлов изображений (.jpg, .png, .webp). Если PDF большой из-за встроенных изображений, сначала сожмите изображения —или используйте PDF Compressor, который обрабатывает оба.
Introduction
PDF Compressor и Image Compressor оба уменьшают размер файла, но target разные типы файлов и используют разные техники. Сжатие PDF работает с multi-page документами, содержащими текст, изображения и векторы. Сжатие изображений работает с single-image файлами (JPEG, PNG, WebP). Какой использовать зависит от типа файла.
Step by Step
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Compare what they compress
PDF Compressor: reduces PDF file size by optimizing embedded images, compressing text streams, removing duplicate objects, and stripping metadata. Image Compressor: reduces image file size by adjusting quality (JPEG), optimizing palette (PNG), or converting format (WebP).
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Compare techniques
PDF: recompress embedded images (JPEG quality reduction), deduplicate shared objects, compress content streams (FlateDecode), remove unused resources, subset fonts. Image: quantization (reduce color depth), DCT compression (JPEG), dictionary compression (PNG), transform coding (WebP).
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Compare quality trade-offs
PDF: text remains crisp (vector), images inside may lose quality. Overall document readability is preserved. Image: direct quality loss — JPEG introduces artifacts, PNG loses color precision, WebP balances quality and size. Image compression is more visible because the entire output is a raster image.
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Compare use cases
PDF Compressor: large reports, scanned documents, ebooks, print-ready files, email attachments. Image Compressor: web images, photos for upload, social media, thumbnails, CDN assets. If your PDF contains mostly images (scanned doc), both tools can help — compress images before embedding.
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Decide based on your file
File is .pdf: PDF Compressor. File is .jpg/.png/.webp: Image Compressor. PDF is large due to images: extract images, compress with Image Compressor, rebuild PDF. Need to reduce email attachment: compress the file type you have. Need web optimization: Image Compressor for assets, PDF Compressor for downloadable docs.
Examples
Same content as PDF vs Image
Input: A 10-page report with charts:
- As PDF: 5 MB → PDF Compressor → 1.5 MB (70% reduction)
- As PNG screenshot: 3 MB → Image Compressor → 500 KB (83% reduction)
Output: Image compression achieves higher ratio for raster content. PDF preserves text quality and multi-page structure.
Common Problems
- Scanned PDFs are images: a scanned PDF stores each page as a raster image, so PDF Compressor applies image compression internally — compress the source images at high quality before scanning for best results.
- JPEG artifacts in PDFs: aggressively compressing embedded JPEGs in a PDF introduces visible blockiness — use quality 75-85 for photos and keep text as vector for crispness.
- PNG has no lossy mode: PNG is lossless, so Image Compressor can only optimize palette and metadata — convert to WebP or JPEG if you need aggressive size reduction for photos.
- PDF text reflow: PDF compression does not reflow text, so removing metadata or compressing streams reduces size without changing layout — but OCR on scanned PDFs may shift text positions.
Tips
- Compress images before embedding them in a PDF — this gives you per-image quality control and better results than compressing the final PDF alone.
- Use PDF Compressor for multi-page documents where text quality matters, and Image Compressor for single images where aggressive quality reduction is acceptable.
- For web optimization, convert images to WebP format (smaller than JPEG/PNG) and use PDF Compressor only for downloadable documents.
- If your PDF is large because of embedded images, extract the images, compress them with Image Compressor, then rebuild the PDF — this two-step approach gives the best size reduction.