Sending a 'pm' - what am I doing wrong?

[pidgeonpost]

I've sent a couple of 'pm's in the last couple of days, and although one appears to have been sent succesfully (i.e. it appears in my 'sentbox'), the other which I've had two stabs at seems to be stuck in my outbox. It does contain a couple of photos - could that be why?
Any clues please folks??

 

[wizer]

the PM will stay in your outbox until the recipient reads it. At which time it will move to your sentbox.

 

[pidgeonpost]

... many thanks!