800 is probly fine. PB and Tinypic suggest 640 for boards, but yours are fine - and they really are lovely. I see from the pic data that you shot the seahorse with a Canon PowerShot A720 IS, and I suppose the other pics too. Nice shooting...!
Thanks. All my pictures are taken with that camera (which I by the way is very pleased with). They don't make that model anymore, so I hope mine will last long.
The only pic my husband took that I posted is, the spotted trunkfish. He has a Canon Powershot D10 (that doesn't need an uw housing but isn't suitable for diving as you can only take uw pics down to 30ft with it) but we were only "so so" pleased with that camera. It was new and it might take another trip to get a better opinion. We thought too many pictures came out blurry, even regulary shots on land.