I have photographed around 100 tennis players for Wikipedia. For each hour of photographing, which could cover two to ten players, it takes about two to three hours of processing to get the photos to Commons. That covers
uploading the photos from my camera to my computer
identifying the players (this can take a long time, especially as ATP/WTA photos bear little resemblance to the players on the court, and if the players are from the same country with the same colour hair! sometimes I have to upload them to Flickr first to get confirmation of correct ID)
choosing the most appropriate shots for Wikipedia
writing image descriptions (including finding appropriate categories for Commons)
preparing an upload script
uploading to Commons
cropping all chosen images
preparing another upload script
uploading to Commons again
adding the photos to Wikipedia articles.
Incidentally if you want to use some photo of mine at Flickr, please ask me to upload the original here (I gladly will) instead of transferring it yourself. It's neater if I can keep track of my own photos.