I'd rather see the opposite encouraged - one image per member, but the post may be edited at any time during the month to submit a better entry.

I'd also like to see a requirement that submissions are shot after the contest commences, not recycled from the archives.

Finally, I've never understood why the contests stand seperately from the gallery - I think it would encourage participation if members could simply link to gallery submissions instead of preparing a smaller version for the forums.

(As a side note: on one forum I participate in, there is a simple non-material prize for winning the monthly contest - the winner chooses the theme for the following month)