How to make the PDF
Drop in your pictures: JPG, PNG, WebP, GIF or BMP. Drag them into order, turn any that are sideways, and choose a page size. Same as image makes each page exactly the size of its picture; A4 and US Letter fit the picture on a standard page, turned to match. Press Make PDF.
Your photos, untouched
A JPG goes into the PDF byte for byte, so there is no second round of compression and no loss of quality. Photos taken sideways on a phone are turned the way they were meant to be seen.
Questions
Are my photos uploaded?
No. The PDF is made in this page, on your device.
Can I use iPhone HEIC photos?
Browsers can't open HEIC yet. Convert them to JPG first, or set the iPhone camera to "Most Compatible".