My question is regarding a hidden file inside another file. However, it is not a specific problem I have about programming (that discards StackOverflow, I think) but instead a "How does it work?" question.
My question is:
I know I can build a .rar file with regular method or programs, and append it to an image by using a command such as
cat img.jpg myfile.rar > img.jpgand when opening the image, the image will be displayed as before. But I can also open the image with WinRAR or a software alike (like
unrar e img.jpg). How is possible that the rar file is recognized inside the jpg image, instead of rejected as not being an appropriate file format?
But, seriously, I cannot figure in which site is it appropriate to ask it (perhaps the question even exists in such site and I am not aware of it, because I don't know the appropriate site from start).
Where can I ask this question?