Was it created as minimal size?
It contains jpeg, but only 2307 B.
So no problema.
$ gpg mail/dspam/dspam.gpg
pub 4096R/7D54EFF5 2011-02-04 Tom Hendrikx <tom AT whyscream.net>
uid Tom Hendrikx <tom AT tomhendrikx.nl>
uid [jpeg image of size 2307]
sub 4096R/D1EA1D1D 2011-02-04 [expires: 2013-02-03]