How can I make a smaller PDF from photos?
Start with sensibly sized JPG images and avoid camera originals that are much larger than needed. Just PDF Tools does not secretly lower image quality during conversion and does not offer PDF compression yet.
Use the toolPhotos to PDF→Resize before converting
For reading on a screen, photos usually do not need their full camera resolution. Export smaller copies in your phone or image editor before creating the PDF. Keep the originals separately.
JPG is often smaller than PNG
For ordinary photographs, JPG usually creates a smaller source file than PNG. PNG remains useful when sharp text, line art or screenshots matter. The final size mainly depends on the number and size of the source images.
Check before sharing
Open the downloaded PDF and zoom in on small text. If it is hard to read, return to a higher-quality source image. If the PDF is still too large, use a trusted PDF compressor and check its privacy terms first.