Sometimes we need to edit the PDF images. Although we have different options to do this, but here I am considering using the preview app installed in the Mac. Mostly, after editing in preview, we face two issues:

  1.  The edited portion in preview app is not shown in the final pdf document generated via Latex
  2. On saving the edited image in preview, preview adds extra spaces to final image

Solve First Issue:

After editing the image in preview,  save image  using Export as PDF… option from the File menu.

Full details can be found at this link.

Solve Second Issue:

This issue is solved within the Latex itself by using the trim option. For example,

\includegraphics[trim=left bottom right top, clip]{abc.pdf} 

Full details about this can be found at  this link