Image to PDF: when to use JPG, PNG or another source format
The best source format depends on whether the image contains photographs, sharp text, diagrams or transparency.
JPG is efficient for photographs
JPEG compression works well for camera images and continuous-tone photographs. It can keep photo files relatively small, but repeated saving can introduce visible compression artifacts.
For photographed documents, inspect small text and signatures before converting to PDF.
PNG preserves sharp edges well
PNG is lossless and is often a good choice for screenshots, diagrams, UI captures and text-heavy graphics. It can be larger than JPG for photographs.
Transparency in the source image may be flattened against the page background during PDF creation depending on the workflow settings.
Page size and image fit matter after format choice
A good image source can still produce an awkward PDF if it is cropped or stretched. Choose page size, orientation, margin and contain/cover behaviour based on how the result will be read or printed.
Rotate phone photos before conversion so every page has the intended orientation.
Image PDFs are not automatically searchable
Placing an image into a PDF does not create selectable text. If search or copy is required, run an workflow after creating the PDF or use a searchable-PDF conversion designed for the source images.
Keep the original images until you have checked the final PDF.
Practical checklist
- JPG for photographs
- PNG for sharp text and graphics
- Choose page fit carefully
- Use when searchable text is needed