📚 Guides

KBPDF Guides

Plain explanations of the things that actually cause trouble: hitting an exact file size, choosing a format a government portal will accept, and what document encryption really protects.

How to Hit an Exact KB Size Without Ruining Your Photo

Why the quality slider never lands on the file size you need, how an exact-KB compressor actually finds the answer, and when you have to cut resolution instead of quality.

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PDF Passwords: What Actually Protects Your File and What Is Theatre

A PDF has two different passwords and only one of them is real security. What AES-256 encryption actually does, why permission flags can be stripped in seconds, and which one you need.

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Why Your Form Photo Keeps Getting Rejected

Upload errors on government and exam portals usually come from a handful of causes. How to read the requirement properly and fix each one, including the minimum size nobody mentions.

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What AES-256-GCM Actually Does When You Encrypt a Photo

Key derivation, why the iteration count matters, what authenticated encryption detects, and why an encrypted photo is deliberately not an image any more.

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JPEG, PNG or WebP: Choosing a Format for Form Uploads

Why PNG makes photographs enormous, why JPEG ruins signatures and text, why WebP gets rejected by government portals, and how to choose correctly the first time.

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