You indeed need to upload the profile picture again. You can do so from the User Control panel which can be access near the top left where it says User CP. Then you need to click on Edit Profile Picture which is the third option down.
Here is a link to make it easier to get to:
As for your signatures, those need to be reloaded. You can do that from the User CP >> Edit Signature. Here is the link for easy access to edit your signature:
Note: You will be able to upload 2 images for your signature but they will need to be 500x100 or resized to fit. This is to limit the amount of scrolling needed on the pages.