What you need to do is go into Android Settings, Apps (or Manage Applications), and then show the "All" list.

In Gallery settings, scroll down to the "Launch by Default" section where you find a button to Clear defaults. Tape that.

Then the next time you open a picture, Android should give you choices again.

The clear defaults button is not active. Also it does say NO DEFAULTS SET. I'm android set emails it still let's me choose. But in the Firefox browser it still says can't find it, and pulls a blank page.

Try checking the "Photos" app for the same setting. Unfortunately Google makes clearing the default quite difficult as you need to know the name of the app that is the default.

There was no exact app for photos. But found one similar, cleared default, no results. Found the Firefox app and cleared the default, still no results.

Could you check the menus of your photo viewer to see whether those provide any hints about which app it is? With so many apps in the world, it's really hard for us to guess which one it might be.

I don't see a photo viewer. And every app I see does not have an active "clear default" button.

When you open a photo, is there any way at all to identify what viewer is displaying it? If you try the menu button or touch around the screen, anything?