GUIDES

Guides

The questions the tools do not answer on their own. Every page here ends at the tool that finishes the job, which is the rule that decides what gets written.

Sizes

YouTube Thumbnail SizeThe size YouTube actually asks for, which is not the one most pages still print.

Formats

What Is a WebP FileThe format you did not choose, saved from a web page, and now something will not open it.
AVIF vs WebPAVIF wins on size. Size is not the only thing you are choosing between.
JPEG vs PNGOne rule decides almost every case. The exceptions are the part worth reading.

Compression

Lossy vs LosslessOne of them discards detail you can never get back. That is usually the right choice.
How to Reduce Image File SizeTwo different operations get called this. Most of the time you want both, in a particular order.

Transparency

What Is an Alpha ChannelA fourth number on every pixel. The values in between are the ones that matter.
The Transparent PNGMaking one is the easy half. Keeping it transparent all the way to wherever it is going is the other half.

Subtitles

What Is an SRT FileA plain text list of lines and the times they appear. Opens in any editor, and breaks on one character.
SRT vs VTTNearly the same file. One of them works in a browser video element and one does not.

PDF

How to Merge PDF FilesJoin documents end to end in the order you choose. What survives the join, and what does not.
How to Split a PDFTwo different jobs share the word split. Work out which one you want first.
How to Rotate a PDF and Save ItRotating the view and rotating the file are different things. The first one snaps back.
How to Combine Images Into a PDFOne image per page, in the order you set. Two decisions, and one thing that catches people out.

What this site does with your file

Which Tools Work OfflineTwo different claims get made about privacy, and only one of them is true of every local tool.