Help me understand what your problem is. What OS are you running? Where are you clicking that one right click shows options Open and Preview. I assume it in some sort of file list. Normally on a windows machine there are applications associated with file type extensions and I would not expect in an application like Windows file explorer that Photoshop would be opened for all files types or that the Open and Preview would always be set to the same application.
In fact in windows file explorer a right click may show different option for different file types. All file types may not have an Open and Preview option. Association may also be change on you when you install an application. On my system many image file type association for Right Click Open and Preview have been set to Photoshop However .jpg has not for preview open Windows Photo Viewer. The Windows Control Panel File Association applet only seems to let you set the Open application association. The whole window file association thing is a spider web where there are many threads and some may be broken. Depend on how many application bumped into the web.
I am on a windows 7 mashine.
I am using the file explorer when I right click
and it is .jpg file I am trying to "preview".
If I change the default program/file association to an other software the peview function works fine. So its only related to Photoshop. It even works with other Adobe software works (Illustrator).
OK so it is windows related some how jpg preview association has been changed to Photoshop. That could have been done during an Adobe update however I have all the updates and my machine still open Windows Photo Viewer. So Its a Windows registry thing. The window's registry is a maze when it come to file type associations. File types like jpeg can be effected by several keys like .jpg, jpegfile, jpeg. thi and that. A quick look in my registry one place I see jpeg associated with windows photo viewer in in the key area for jpegfile.
Well I checked the reg file you point to in your image and I have the exact same data line. So it does not help me very much . There must be a value somewhere in the photoshop registry where it is set to "preview"?
I have tried uninstalling and reinstalling photoshop... No change. Any ideas what I could do?