Why Are My PDF Pages Different Sizes After Converting From JPG?

Each page in the resulting PDF is created at the exact pixel dimensions of the image it came from — there's no resizing to a standard page size like Letter or A4. If you combined photos taken at different resolutions or aspect ratios, the pages in your PDF will be different sizes too. This isn't a bug: it's how the tool preserves your images at their original dimensions rather than cropping or stretching them to fit a fixed page.