[Jason Green]

First-off, it sounds like a good idea for a site, good luck!

Now, I think this is quite simple, really. Jenny, you asked a website owner for their permission to use their photographs of carded specimens on your site. They failed to answer so you now wish to draw their pinned coleopteran pics for use on your site. Therefor essentially you will be drawing a dorsal view of these insects. Correct? If so, it is simply that - dorsal views, and not as if their photos were taken in the field and you copied them exactly including perhaps artistically-captured backgrounds! So it's not copying in my opinion, simply using their images as a base to copy the insect's aesthetics that you could get another way.

Also, you asked for their permission - you took reasonable steps. I'm obviously not saying it is therefor OK for people generally to go ahead without permission who are obviously copying, it isn't - but you did what was expected on your part. Maybe offer to give them a good write-up and obvious credit?

As a third point, feel free to use any images you find on my website with credit!

Well, these are just my opinions, and I am the same as them - a website owner and photographer. Therefor my stance on this is the same as it would be if I was in their position.