Why WebP files need converting at all
WebP is excellent on the web and awkward everywhere else. Email clients preview it unreliably, office software often refuses it, print shops ask for something else, and many online forms accept only PDF or JPG. Putting the images into a PDF solves all of that at once: a PDF opens on every device, prints predictably, and keeps your pictures in a fixed order.
That order matters more than people expect. Photographs of a contract, pages of a form or a set of receipts have to arrive in sequence, and a folder of loose image files does not guarantee it. One PDF does.
Page size, margins and orientation
Fit to the image makes each PDF page exactly as large as the picture on it. Nothing is cropped, nothing is padded, and the PDF is the smallest it can be. This is the right choice for screenshots, diagrams and anything that will be read on a screen.
A4 or Letter puts each image on standard paper, centred, scaled down if it is too large and never scaled up, because enlarging a small picture only makes it blurry. Choose this when the PDF will be printed or submitted somewhere that expects a paper size. Orientation can follow each image automatically, so a wide photograph gets a landscape page without you doing anything.
What happens to your photo data
Photographs carry more than pixels. EXIF data can include the camera model, the date, the settings and, on a phone, the exact place the picture was taken. Sending that to a stranger along with a scanned document is a real privacy problem, and most people do not know it is there.
Because every image is drawn on a canvas and re-encoded for the PDF, none of that metadata survives. What goes into the PDF is pixels and nothing else. We mention it not as a feature to boast about but because it changes what you can safely send.
Nothing is uploaded
Files are not uploaded - everything happens in your browser. Your images are read locally, the PDF is assembled in memory by JavaScript running in this tab, and the finished file is handed straight to your downloads. There is no server copy, no queue and no account.
One useful consequence: the number and size of files you can convert is limited by your own device rather than by an upload cap. On a laptop you can comfortably put dozens of images into one PDF.