I have a winodws 8 Laptop. If I put tags in my jpegs, can I use these tags to search jpeg files on other windows / linux machines? Or I have to use specific application to do so.
Tags are supported by the JPEG format. Windows 8 supports the standard. You will be able to use these tags on other Windows and Linux machines.
For more information, you can see this post: http://beckustech.wordpress.com/2013/03/12/tagging-jpeg-image-files/