We could do daily CheckUsage for images and count on a
day-by-day
basis. Or just once a week. Or once a month. These will average out
over time.
Err... don't we have logs of the access to the image files themselves (including
thumbnails)? It would be MUCH simpler to analyse those than to look at page
views and then at image usage and then infer how much an image is loaded...
Basically, there are two interesting figures:
1) "On how many pages is a given image used?" (maybe also "on how many
different
wikis")
2) "How often is a given image loaded?"
What has been discussed so far is "how often are pages that use the image
loaded", which seems to be besides the point...
-- Daniel