Shower Stall - Drywall joint cracking

[DD716TED]

I have noticed in several places around the top of the fiberglass shower stall where it joins with the wall board, small cracks are starting to develope where the original caulking was installed. (see attached picture).. I want to fix these small cracks before mositure can get through them.. First off I don't want to remove the existing painted caulk as I am worried that I might damage the drywall.. What type of material should I use and how do I apply it to fix these cracks? All suggestions appreciated. The attached picture is magnified.. the section shown is about 3 inches long..

[HayZee518]

white bathtub caulk not silicone. DAP makes it.

[Drywall DIY Guy]

Cracks

I would just fill them with the DAP caulk HayZee518 recommends. Fill the crack and smooth it out. 5 minutes and you are done for a few years.