Yeah, I think I read about it somewhere awhile back, never tried it tho. Looks good for a HL1 modification, but they could hold back on the sharpen filter on the textures somewhat.
Heres a simple java script I found to do the image popup windows.
This part goes in above your <body> tag and below your tag.
<script language=javascript>
</script>
And here is how you link the images (I used one of your images as an example) to the script:
[img=level/duckhunting/stuttgart_03.jpg][/code]
I hope it helps you, I found it on one of my old websites.
ping in the editor?
Hmm Ive had that from time to time aswell and I have just rebooted to fix it. My problem atm is that all maps I save are corrupted everytime I open them again.