I think there has been far too much uploading of images without thought as to use, and in some cases with blatant disregard of the image copyright. The latter is especially serious as copyright violation has been a crime in the UK since 1989, and in the USA since about 2000. I have just a few minutes ago had to delete three images on the grounds of copyright violation, and I suspect there are many more.
Always remember that just because something is within your reach, that does not give you the right to take it (the childhood doctrine of "finders keepers" is false; the law calls it "stealing by finding"); this means that you cannot simply upload an image here just because you "found it on the web somewhere".
Images must only be uploaded because you are about to use them in an article, and must also not be duplicates of existing images (unless the previous version is of lower resolution or otherwise faulty, in which case the new image should if possible be uploaded over the old one, or if not the old one should be tagged for deletion). I have previously had to delete images on the grounds of being pointless duplicates, even though both versions have been uploaded by the same person.
Anyone who spots an image which is dubious should report it to the admins (the current ones can be seen by going to Special:ListUsers/sysop; if the "Last edited" date isn't within the last 60 days, that admin is inactive and there's no point in contact) or by posting to this blog. Certainly I feel that a massive purge of files is overdue; we seem to have focused on quantity instead of quality.