A lot of my pictures show as the default symbol on my Pantech Jest 2. I just activated it yesterday. The symbol looks like two photographs with white hearts in them and blue backgrounds. If I try to click on one and set it as a contact ID, there is a message that says unavailable. Also if I rotate a picture, a lot of them that I was previous able to view switch over the the default symbol. And every time I turn my phone on, it takes about 3 minutes to load pictures/music/sounds etc.
Do you have your files saved on an SD card? You should format the card while it's in the phone. (Formatting erases everything on the card, so make sure your stuff is saved to your computer first!) The option should be in your settings under memory/media card. This will add the folders so your phone can read the files. Copy your files back to the card, and restart your phone.
Regarding the time to load, the only thing you can do -- besides not turning off your phone -- is keep only the stuff you really need. The phone just doesn't have the power to quickly load a lot of files.
Enjoy your new Jest 2!