Tutorial: Error Level Analysis
http://fotoforensics.com/tutorial-ela.php
Briefly ....
Error Level Analysis (ELA) permits identifying areas within an image that are at different compression levels. With JPEG images, the entire picture should be at roughly the same level. If a section of the image is at a significantly different error level, then it likely indicates a digital modification.
Look around the picture and identify the different high-contrast edges, low-contrast edges, surfaces, and textures. Compare those areas with the ELA results. If there are significant differences, then it identifies suspicious areas that may have been digitally altered.
In the earlier photo of the doc and army helpers it can be clearly seen that the doc and first aider have different textures to the army personal suggesting they have been digitally added to the image.
Here's another example...
http://fotoforensics.com/tutorial-ela.php
The original image was resaved one time. To the human eye, there is no visible difference between the original and the resave image.
The resaved image was digitally modified: books were copied and a toy dinosaur was added. ELA clearly shows the modified areas as having higher ELA values.
Much the same as the apparent women survivors covered in dust...
Also notice the yellow tape appears purple whist the yellow logo on the pot bellied woman is white and the mans trousers are not consistent with his shirt.
OK, it's not conclusive proof but ELA combined with image enlargement techniques quickly raise suspicions that certain images we are shown by the media have been modified and are not what they appear to demonstrate, and if that the case then an individual has to draw his own conclusions as to the actuality of the event the images are portraying.
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