Have new 27" Mac unable to access my Iphoto apps. and others, how do I contact developer and find my pictures

iPhoto was discontinued almost 7 years ago. It is no longer developed or sold. It was replaced by the more powerful (and free) Photos.app that comes with the OS. You can migrate to that app very simply:

Hold down the option (or alt) key and launch Photos. From the resulting menu select 'Choose Library' and point at your iPhoto Library. It will do the rest.

If you prefer not to use Photos there are several 3rd party apps that you can use. Which to choose depends on the kind of photographer you are and your budget.

1. Picasa no longer exists. It was killed off by google 10 years ago.
2. The MS apps can be updated by purchasing a new licence for the current versions of these apps.
3. Contact Garmin for assistance with their app.