Holy Pickles, Batman!

For Christmas, Jill got me a pressure cooker. I know that sounds like an odd gift for a wife to get a husband but she found out that I was thinking of getting her one and made sure I knew she didn't want another kitchen gadget. So a few days later on Christmas morning, I unwrapped a pressure cooker. I started making pickles that day. As you can see from the picture they look so good in the jar and the jars sealed great! However, when I opened one a day later they were all mushy. I mean really mushy. So, when I have time again I want to make another batch. I have heard that I need to make sure I get fresh cucumbers. Is that true? Does anybody out there make homemade pickles? If so, what's your secret?.....you can tell me I won't tell anyone. :)