We've all been there: you try to email a report, only to be told it exceeds the 25MB attachment limit. Or you try to upload a resume, and the portal rejects it for being too large. PDF files can become bloated surprisingly quickly, but understanding why can help you fix it.

Why Are My PDFs So Huge?

PDF size usually comes down to three culprits:

• High-Resolution Images: A single 4K photo embedded in a PDF can add 5-10MBs alone.
• Embedded Fonts: To ensure your document looks the same everywhere, PDFs often store the entire font file inside the document.
• Vector Graphics: Complex charts and architectural drawings contain thousands of individual paths that add up.

Strategies for Compression

1. Downsample Images

For screen viewing, images rarely need to be more than 150 DPI (dots per inch). Many print-ready PDFs use 300 or 600 DPI. Reducing this resolution is the single most effective way to cut file size. It can often reduce a file by 70-80% with barely noticeable quality loss on a monitor.

2. Remove Unused Objects

PDFs often contain invisible "garbage" data—bookmarks, metadata, and history states—that aren't needed for the final view. A good compression tool will scour the file structure and remove these redundant elements.

Using Andromeda to Compress

Our resize/compress tool uses smart algorithms to balance quality and size. We specifically target the image streams within the PDF structure, re-encoding them to more efficient formats while maintaining readability.