Why your exam photo keeps getting rejected
9 min read
Online exam forms reject photos for reasons they rarely explain. Here is what each one checks — pixels, kilobytes, ink colour — and how to pass first time.
Blog
Guides to the file problems people actually hit — why a form rejects a photo, why a file will not upload, what is inside a document besides the words. Each one is written from the specifications and tested against real files, and says plainly where the limits are.
Why your .m4a file will not upload anywhere
8 min read
M4A is the better format and almost nothing accepts it. Here is what is actually inside the file, why renaming it to .mp3 never works, and what to do instead.
Is it safe to use online PDF tools?
9 min read
What “we delete your files after an hour” actually promises, what a privacy policy cannot cover, and how to check any file tool yourself in about two minutes.
DPI explained: why 300 DPI does not make your photo sharper
8 min read
An image file has no physical size — only pixels. Here is what DPI really changes, when it matters, and why setting it to 300 does nothing on its own.
Why a platform labelled your real photograph as AI
9 min read
Content Credentials travel inside your photo, and one touch of an AI tool can tag the whole file. What the label means and why it is so often wrong.
Lossy, lossless, and what “quality 80” actually throws away
9 min read
Every compression slider is making a decision for you. Here is what JPEG discards at each setting, why PNG behaves differently, and where the visible cliff is.
Is your PDF scanned or real text? How to tell, and why it matters
8 min read
Half the PDF tools that “do not work” fail because the file is a picture of a page. Here is how to check in seconds and what each kind of PDF can actually do.
Everything inside a PDF besides the words
9 min read
Author names, software versions, timestamps, cropped-away image data and filled form values all travel with the file. Here is what is there and how to look.
How to put a photo and signature in one image for a form
7 min read
Some forms want the photograph and signature as a single upload, in a set layout. Here is what they are asking for and how to produce it without a photo editor.
The honest limits of browser-based file tools
9 min read
Processing files in the browser removes the upload, not the limits of the format. What a browser genuinely cannot do, and when you still need real software.
Original measurement, not opinion: we tested what 15 online file tools upload.
Read the test