Cache or cookies: what should you clear?
A useful first step when a website looks wrong, forgets a setting, or will not sign you in.
5 min read
A LITTLE KNOW-HOW GOES A LONG WAY
Less guesswork.
More know-how.
Straightforward guides for the things you do online. Find a useful answer, understand the why, and get on with your day.
Explore guidesInternet & browsers / Files & formats / Privacy & security
THE STARTER COLLECTION
A good place to start
Small questions. Useful answers.
PNG, JPEG or WebP? Pick the right image format.
A practical starting point for photos, screenshots and images with transparent backgrounds.
5 min read
Changing a file extension is not converting a file.
Why renaming photo.png to photo.jpg does not create a JPEG—and what to do instead.
5 min read
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Practical guides
Guides with sources, comparisons and practical examples. Keep an original copy before changing files or settings.
LUMOTOPIC / Tools
Tools & resources
Image converter
Convert PNG, JPEG and WebP images, adjust quality and resize a copy.
Convert imagesBefore you convert
A short checklist for choosing an image format and checking the result.
Download checklist (.txt)Good information should feel simple.
A useful guide helps you take the next step. That is the idea behind every page here.
01
Get to the point
The answer first. The details when you need them.
02
Know the context
Understand what changes, and what to look out for.
03
Read in your language
One idea, explained with your language in mind.
LUMOTOPIC, EVERYWHERE
A world of questions. Your language.
Choose the language that feels like home.