Hello Sir Ji, Its been a while I've Shared any note with you.
There are too many unknown file extension that we even heard of first time and thinking about opening them is a far thing but atleast you can try to open them or fix without any software. Some files have .file extension that's toally a SH*T, I can't figure these things out why all OS have different extension support no one can use its official working softwares on MAC because in terms of Work, MAC (I'm sorry#Apple but) really SUCKS. So let's divide things into some parts, this time only small files:
1. With .file type or .unknown(I mean anything type)
Try replacing .file with .rar, .tar if it opens with you WinRAR Software, its done but if its still not done try opening it with NotePad (not always open with NotePad, it will become a big mess further). NotePad is the actual king of Software, it can open any file in this world but not always right or good to do things with it.
2. Clicking on Image opens Image in Browser?
If you see the exact picture you're you want inside browser but why do anyone want to see Photos in Browser? first see if the file has extension of .php, .html, .asp or similar to that, again try changing it to .jpeg if its done, good but if not then its Developer Time, Just click F12 from Functions key to Open Developer Tools and Hover Pointer Over Image and get its Exact Location or for Firefox - "Right Click > View Page Info > Media" and grab all Media files from the List given there. Same with Other Browsers but from DOM.
Developers will figure out, what I'm Saying.
3. Nothing for now, time to go as it was a Quicky. See Ya with Big Files.