There was a problem with direct linking about a year ago which was discussed here with an eye to some things to check.
http://form.pbase.com/viewtopic.php?f=6&t=47544 I personally have never tried to link to stuff in my 'in box', in fact I never use it. I could suspect it might be treated differently as it's a sort of special gallery, but I think you're saying it had worked for you in the past? Have you tried linking to an image in a gallery besides your 'in box'? My website has some direct links to a few of my own PBase images in non 'in box' locations, and I just checked; they seem to be working OK.
Dunno, we seem to get these periodic waves of strange behavior. An email to
support@pbase.com might be in order, as they don't necessarily pass through here too often.
DaveT