You have transparent background when you're view the picture. No?
BTW: Transparent background? What do you mean?
----
As for me, I needed
1) ratings for the images (photos)
2) discussion for each image (photo)
3) top 10 (50?) preview by best average rating, most preview etc.
4) it's better to have separate page for each photo/discussion like in the blog for the theme/discussion
I.E. not only the image, but the photo gallery. Yes, It is possible to implement it using the blog or to make it by hands with pages+html content+.. Or make some feature mix using blog and image gallery. I do not know yet which is the better way. I will have 1000+ photos per site. I 'll appreciate your opinion.
Regards.