When a PDF page should become a PNG
Both picture tools here draw the same page at the same resolution. The difference is what happens to the detail: a PNG keeps every pixel exactly as it was drawn, and a JPG throws some away to be smaller. That trade is a good one for photographs and a bad one for anything made of lines and letters. This page says which is which, and covers the switch most people miss.
Which tool you need
A page of text, a table or a diagram
PDF to PNG. Compression artifacts collect around sharp edges, and every letter is a sharp edge, so a page of type is exactly where JPG looks worst.
A logo, a stamp or a signature to drop onto something else
PDF to PNG with the transparent background turned on. Anything the page leaves unpainted stays see-through, so the mark sits on whatever is behind it instead of in a white rectangle.
A page that is mostly a photograph
PDF to JPG. A photograph has no hard edges to protect and a PNG of one is several times the size for no visible difference.
Somewhere with a file size limit
JPG, or a lower resolution here. PNG files are larger by nature and there is no quality slider to trade away, because keeping every pixel is the point of the format.
The words need to stay words
Neither. A picture of a page is a picture: send the PDF itself, or pull out the pages you need with Extract PDF pages.
The transparent background
Left off, the page is drawn on white, which is what you want for a page. Turned on, anything the page never painted stays see-through, which is what you want for a mark you are going to place on top of something else.
It is worth knowing before you convert rather than after: a PNG drawn on white cannot have the white taken back out without editing it somewhere else.
Size, and what to do about it
A PNG of a page can be several times the size of the same page as a JPG, and that is the format working as intended rather than a setting to fix. There is no quality dial, because a PNG that threw pixels away would be a JPG.
The dial you do have is the resolution. Dropping from 300 to 150 halves the picture in each direction and quarters the file, and for anything that will only ever be looked at on a screen it costs nothing you can see.
What to know before you start
- A single selected page comes back as one file; anything more arrives as a ZIP, numbered by page so a folder puts them in reading order.
- The picture cannot be searched or selected, and links and form fields stop working, because the page has been drawn rather than carried across.
- A locked PDF has to be unlocked first, and every page is drawn in your browser rather than anywhere else.