You would need to post a url here if you want us to suggest anything about graphics but I would assume here your using a custom vb
style and as such you need to modify your style in vb
admin and make sure you correct in the styles admin the relative image paths and make them full urls so photopost knows where to find the images.
As far as login on install did you properly enter the vb
license number from the config file to your config in Photopost? If not you can correct this by entering it now in the config-inc.php file
Did you specify the proper vbulletin cookie prefix on install? By default it is bb and if you do not enter it you will not get into photopost admin cause we can not authenticate you since both the cookie prefix and license number along with user password make up the password cookie in vbulletin.
At this point you need to post a url so I can see where you are on install.