Anytime Greg, I am quite pleased to be able to give something back to the community that has given me so much!
I really like the way you are doing it. Instead of using the IMG tag and embedding the pic, you let people choose to look or not. Dial Up User Friendly. I would use this approach if the file is over 50kbytes is size.
If you try adding / to a url you will quickly find that many websites do not directly allow browsing of the directories. Not Allowed If you see a html file load it is because a default file was specified. I assume not all hosting services will allow it either, so this approach may not work for everyone.
Think I will fix my habanero post the same way if I can. Even though they are small files, in total they are nearly 1MB. That post would take a dial up user up to 5 minutes to load.