A “reverse image search” allows you to search the internet for previous versions of the same picture. This is crucial for determining if an old image is being “recycled” as new. Especially during emergencies, old pictures are often posted online, and go viral due to uncritical re-sharing through social networks (this happens regularly both during complex emergencies and natural disasters).
Further, a reverse image search can also allow you to track down the original uploader of an image.
Tip: A reverse image search can also be highly useful to track down previous versions of YouTube videos! In this case, perform a reverse image search with the thumbnails that are created by YouTube when uploading a video (all three thumbnails created by YouTube can be extracted through the YouTube Data Viewer).
Photo: Screenshot of a video from the Syrian conflict after it has been removed by YouTube. Screenshot taken from YouTube.
The most compelling evidence of a human rights violation captured on video can be lost if investigators do not save the video in question. YouTube videos are often removed, either by the uploader themself, or by YouTube because of violations of its community guidelines. It is thus most crucial for any researcher to first save any video that is being investigated. This is for preservation purposes only.
Videos on YouTube are only showing the upload date, but not the exact time of upload. This can be important to find the original uploader of a video, and also helps to avoid confusion and incorrect claims about the upload date. The most prominent example for this was the false claim by Russian authorities that the chemical weapons attack in Syria from August 21, 2013, was staged, since some of the videos showed an upload date of August 20.
Panoramic images or photo mosaics from videos are often used in human rights research, and are especially useful for matching up visual features such as landmarks with satellite imagery. For example, Human Rights Watch used a photo mosaics in a January 2014 report on housing demolitions in Syria (see p. 22). A more detailed case study in the use of panoramic images can be found here.
For the following tutorial, I am using a video from Aleppo.