How to set Windows Photo viewer as default program when viewing photos

I know it's been a while, but this question isn't fully answered. So what if Windows Photo Viewer isn't listed in the the list of programs?

FALSE.  I can associate other file types (JPG, BMP, etc) because when I look at the list of available programs, Windows Photo Viewer appears on the list and I use it all the time.

But when I try to do the same with a GIF file, Windows Photo Viewer isn't in the list.  The program exists, but how can it be found (by hitting "Browse") so that it may be associated it with a picture file type?

That was the question being asked.  You gave a lazy answer.

Still not answered - What changed ?  gif's used to be recognized and associated with windows photo viewer ?

where can you set the association ?

not in control panel as answered earlier !!!!

Windows photo viewer is part of the shell, so it behaves differently to a stand-alone program.  You can't 'browse' for it from 'open with' interface.  It also appears to handle associations differently in the Windows registry, e.g. there doesn't seem to be a single 'supported file types' list, like there is with stand-alone programs.

I have never found an installation of Windows that doesn't have 'photo viewer' as a default option for 'open with/'other programs' for all image types that it can handle (e.g. gif, png etc) - I assume that you know you have to click the little 'expand' icon to the right of the "Other Programs" heading before you'll see them all, otherwise you just see the 'recommended programs' (which will not generally include photo viewer, even for compatible file types).

Another option is what Microsoft said - use 'Default Programs' in the control panel.  I find 'Default Programs' more robust than 'open with', but you should try selecting 'choose defaults for this program' instead of 'set as default' - this will give you a list of all file extensions that photo viewer thinks it can handle (with checkboxes), and you can see if 'gif'/'png' are present.

If they're there, but ticking them doesn't work (i.e. the images still open in another program), then the other program may be 'locking' the file associations and preventing them from being changed.  You'd be surprised how many programs do this by default, forcing you to delve into the program options to free them up so you can change them back (I find Nero products are usually the worst).

If, on the other hand, they're not there at all, then you have no choice but to edit your registry (because somehow photo viewer has 'forgotten' that it can open these file types).  The problem is that because photo viewer is part of the shell, the command line is complicated:

rundll32.exe c:\windows\system32\shimgvw.dll,ImageView_Fullscreen %1

(you can test this by running it in the command line and putting a path to a valid file in place of the '%1')

This is why you can't 'browse' for it.  'rundll32.exe' cannot be selected as an 'open with' target, and the dll won't work either.  You can't even create a shortcut (containing the command line) and use that as a target.

You'll have to find the registry entry for the default shell open command, and remember to be very careful when editing your registry - read some on-line tutorials if you've never attempted it before.  For png files on my Win7 U64 system, the key is found at:

HKEY_CLASSES_ROOT\pngfile\shell\open\command(Default)

Set the default string to the above (including the '%1' at the end) and it should work (but I haven't tried it - I've done these kind of edits for other file types, but for me, photo viewer was properly registered, and the correct string was therefore already present).

As I said earlier, photo viewer should register all the file extensions it can handle when Windows is installed, so if it isn't in the 'other programs' list (or the extension isn't in the 'supported file types' list), then something or someone has probably been messing with your registry.