I have a couple of standard ways of detecting a modified image such as
are there any other standard ways of detecting a modified image?
Tried out
Here are my questions
The answer to this question needs more detailed so, I will give some references to the subject itself and I will share with you the code of every part of your question :
You need to use exif
to verify the image with metadata
For Anomaly Detection in Images see here
To compare the thumbnail image to the original image read this. where it showed you how to compare two images using Python.
References :