Robert J. Hansen rjh at
Wed Dec 31 15:31:31 CET 2014

> I've been looking for documentation with info on adding a photo id to a gpg key.
> The instructions for adding are available but I can't find any advice for the
> size, format, dpi etc of the image to be used.

The major problem is there is very little good advice about this, and what there is keeps changing.  For a long time the PGP Desktop product used 120x144 as a picture size.  Back when a high-resolution display was 800x600 it made a lot of sense; now, when my laptop has a 2880x1800 display, a 120x144 image is literally smaller than a postage stamp.

GnuPG adopted the photo-ID feature a few years later and technology had already progressed to the point where the GnuPG advice was 240x288.  That advice hasn’t changed in over ten years; it’s probably out of date by now.

With respect to what format should be used, the de-facto standard seems to be JPEG.

I personally don’t find photo ID to be a useful feature.  They’re too static.  The photo ID on my certificate, for instance, is almost ten years old.  If you need photo ID, a better route would appear to be something like, which offers some neat tools for binding a certificate to photographs, social media accounts, and whatnot.

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