Karen, I don't think that is childish at all. They are your photos, and you should be able to delete them for any reason - dissatisfaction with the site and/or administration certainly being one of them. Had I had the chance to do so, I probably would have. I posted a very nice goodbye on my local regional forum on DG when I had decided to leave, which was immediately deleted by the admins. I didn't mention ATP by name, just said I was going elsewhere. I thought that was very paranoid of the administration, not to mention rude. It was shortly after this that they gave me the boot. Shrug. No regrets.
