When patrolling files, there are some things that just stick out as suspicious.
- Facebook metadata: Facebook's CDN automatically removes all image metadata and replaces it with "Special instructions: FBMD..." and "Original Location Code". An image with special instructions beginning with FBMD went through Facebook or Instagram somewhere. Many image editing programs will leave this metadata in even after the image was edited. The appearance of these metadata entries is not enough to delete an image on their own, but you should run a reverse image search and check any relevant Facebook and Instagram pages. Many Facebook images and most Instagram images are not indexed by Google Search By Image, so a lack of results does not mean stop looking.
- A complete lack of metadata: Some uploaders strip metadata for privacy reasons. This is acceptable, if not ideal. Many social media platforms also strip metadata completely. Run a reverse image search. If nothing comes up, try searching relevant websites and social media pages. If an image is high quality (Higher resolution than a smartphone, shallow depth of field that's not from iOS Portrait Mode or similar editing techniques), it is often a good idea to tag {{di-no permission}}.
- An EXIF Copyright or Author field that doesn't match the uploader: Unless you find a direct source and can tag as copyvio, you should tag {{di-no permission}}.
- Pixels and interference patterns: If you can see a grid of pixels, unnatural reflections, or Moiré patterns, it is extremely likely that this is a picture of a computer or TV screen. Depending on the subject, this is often enough to delete the image after a DR or FFD. If you can find a likely source online, tag copyvio.
- Uploader blocked for copyright violations, or has many copyvio warnings: Unfortunately, some people just don't get it. If an uploader has been blocked, especially for copyright violations, you should inspect their uploads very carefully.
- Phrases that imply the uploader is not the copyright holder: If the image was "Sent to me personally", the "Evidence will be provided upon request", or the source is a person, you should almost always tag {{di-no permission}}.
- Posed portraits of living people: Check these carefully: they may be copyright violations, or they may be indicators of COI/paid editing. There are a few websites that release their portraits under a compatible license, check for Commons templates for those.
- Photos of sportspeople in arenas: There are a few photographers who release these images under a compatible license on Flickr, but there are many more who license them to stock photo companies. They may also be screenshots of TV broadcasts, especially if they're from an otherwise impossibly high angle.
- Metadata that indicates Getty Images, AP, Corbis, iStockPhoto, etc... These are copyvio. No exceptions.