When i save a picture on photoshop after i've made adjusments to it, the file will only open with photoshop! how to i get the file to open with pain, or windows fax viewer?

check to see what file format you are saving the file in...by default it is .psd....you can use the pull down menu at the bottom of the save window and save it as a .jpeg,.bmp....etc.

As the other answers have noted, if you save your file as a native PSD (Photoshop document) it will automatically open in Photoshop next time to try to access it. You'll need to save it in a generic format such as a .gif or a .jpeg (File >> Save for Web). If you've already saved your Photshop file into a generic format and it's still opening in Photoshop, you may need to change the program association with the file. Try this:
1. Open the folder where you've save your image.
2. Right click on the image and choose "Open With"
3. Select the program with which you want to open the image.
(you should see a list of the programs you have on your computer, if not go the bottom of the list and select "Choose Program")
4. The dialog that appears will allow you to browse your computer to find the program you'd like to use to open the image
5. Finally, if you want to use the same program to open images in the future, click the checkbox that says "Always use the selected program to open this kind of file".

Hope this helps. Good luck!

The simplest way to do this is open the file in Photoshop, click the File menu and select Save for Web. Then choose JPG as your file type.