On Monday, 10 Apr 2017 at 16:51, Eduardo Mercovich wrote:
> Hi Marvin.
>
>> I also agree that in terms of resolution (pix per inch ) pdf and 
>> jpg are the same. However, pdf (and SVG) allow the image to be 
>> scaled with little loss in image quality.
>
> Sorry to disagree, but again, pdf images can be vector (like svg) 
> and infinitely scaled or raster (bitmap, as a jpg) and in this 
> case the quality is on the file. The pdf format only adds and 
> envelope around the original jpg image, or in the conversion it 
> can be downscaled.

Totally correct.

And, further, pixels per inch (i.e. resolution) is a property of an
output (e.g. printer or screen) or input device (e.g. camera sensor),
not an inherent property of the bitmap image.  A bitmap file simply has
a size which can be expressed as pixels x pixels.  If you display an
image on a high resolution screen (without scaling) it will appear
smaller than if you display it on a lower resolution screen.

-- 
: Eric S Fraga (0xFFFCF67D), Emacs 26.0.50, Org release_9.0.5-385-g72fc2d