It's worth checking to see if iTunes created a backup at some point prior to losing your photos. iPhone Backup Extractor lets you access all saved backups in your computer and retrieve data within those backups. Hope you get your photos back. Here's a helpful article on how to recover lost photos.
Syncing does not cause pictures taken with the device to disappear, never has.
If the pictures were simply synced via iTunes to the device, then they are still on the computer and simply need to be synced back to the device.
As alexandra suggested, the pictures may be included in a previous backup, either restore from a previous backup or try using the solution alexandra offered.
Well, In your situation, I suggest that you have better to use an iPhone Backup Extractor The data can be recovered or not is decided by the file type of the backup file. The iTunes backup file is not a common file, but an SQlitedb file. It's not readable. So even you find the backup file, you can't get the content out of it, let alone restore to your iPhone. With the tool, you can get your lost photos back easily. Good Luck!!
If you have back up your notes, you can restore from the backup.
To restore information from a backup, use one of the following methods after connecting your iOS device to the computer with which you normally sync:
1. Right-click (or Control-click) the device and choose Restore from Backup
2. If you have a new phone, you can connect to iTunes and it will prompt to restore from your backup
Solution from Apple.com: http://support.apple.com/kb/ht1766
If you have no backup for your data on iPhone, iPhone data recovery software is your last shot! I used iTunes Data Recovery and it worked well. It's easy to use. Just a few clicks you can get all your photos back. Here is a step by step guide for you: http://x.co/3Q8U3