What you have done recently should all be accessible under "my profile". If you posted the picture when you started a thread, go to "My Profile" and look under "Find Recently Started Threads". If you attached your picture to a reply, look under "Find Recent Posts". If you have started a Blog with a photo album, then the picture would be there. There is more than one way to do almost everything on the new board.
To keep track of a thread after you post to it, you can subscribe to the thread using thread tools (on the darker beige bar below the name of the thread). If you always want to track threads to which you have posted, then go to "settings" (top of page), "General Settings" under "my account"', "Default Thread Subacription"' (under messages and notification)' click the box. You then can choose how to receive notifications, just on screen (through my control panel), or by email.
You can quickly access threads once you have subscribed to them either through Settings or through Quick Linkson the green header bar.