With regard to uploads from mobiles, there have been several positive discussions on the Commons village pump when mobile applications encouraged uploads.[1]
It is still the case that the significant majority of images uploaded from mobile platforms have to be deleted as either out of scope (like bad blurry selfies) or obvious copyright violations. We even have some bot-categorization of deletions quietly going on to keep a running track of it, and several past experiments to find ways of managing copyvios automatically, shortly after they appear in recent uploads.[2]
As tablets with good cameras and more sophisticated mobiles are used to do more stuff on Wikimedia projects, the trend is improving, but the design challenge remains that mobile apps to which make upload easier need to also encourage upload 'qualification' to reduce the burden on volunteer administrators to do endless housekeeping, and mobile users need coaching/coaxing to consider copyright and educational value before launching their selfies and lolcats on Commons. :-)
Links: 1. Sample past VP discussion: https://commons.wikimedia.org/wiki/Commons:Village_pump/Archive/2013/04#Mobi..., https://commons.wikimedia.org/wiki/Commons:Village_pump/Archive/2013/04#Prop... 2. https://commons.wikimedia.org/wiki/Category:MobileUpload-related_deletion_re...
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