Guides
These are the write-ups we wanted when we were building the tools: what a format actually costs you in size and quality, which limits are real and where they come from, and how the algorithms work. They are published in English and Simplified Chinese only, so that every article gets the same attention.
How Minecraft Locator Bar Colors Are Calculated
The Java UUID hash, Bedrock join-order colors and the Geyser XUID mapping behind locator bar colors, plus /waypoint overrides.
HEIC vs JPEG: iPhone Photos Explained
What HEIC is, why iPhone uses it, how it differs from JPEG, when you must convert to JPG, and whether converting costs quality.
Passport Photo Size Requirements: Pixels, DPI and KB
How passport and visa photo rules work: print size, pixels, DPI, and the file-size ranges upload systems actually enforce — including the minimum sizes many of them reject files for. Plus how to compress without blurring the face.
IBAN Structure and Check Digits
How an IBAN is built, how the MOD-97 check digits are calculated, and what a passing checksum does not prove.
JPEG, PNG, WebP or AVIF?
How to pick between JPEG, PNG, WebP and AVIF: transparency, lossy versus lossless, compatibility, typical uses, and conversion quality.
Why PPT Files Get So Big — and How to Shrink Them
What really fills a PPTX: embedded photos, video, fonts and leftover data — plus the safe order of steps that cuts the size without breaking slides.
AQHI vs AQI: Why the Numbers Differ
How Canada's AQHI and the US AQI are built from different pollutants and formulas, and how they translate through PM2.5.
Local vs Server Processing
How browser-side file processing works, what uploading exposes, and two checks that reveal whether a tool sends your file anywhere.
How to Reduce PDF File Size
Why PDFs get large, lossless structural optimisation versus lossy image re-encoding, unshrinkable scans, signature warnings, and hitting upload limits.