hi,
recently my iPhone 4 jail broken on iOS 5.0.1, accidentally went into restoring mode upon connection to the iTunes, no back up could be done.. how can i recover my lost photos ..
thank you.

If the phone has been restored, the photos could already be lost. That said, if the phone just booted into recovery mode, you can use TinyUmbrella to try and kick it out of recovery. If that doesn't work, iTunes backs up the camera roll to either iCloud or your local machine when you sync, depending on your settings. If it's local sync, you can recover them from your backups. If they were iCloud sync, you can recover them by setting the phone back up and telling it to retrieve the iCloud photos.

If you don't have any backups and you can't kick the phone out of recovery mode, there are custom restore packages out that leave the data partition alone, specifically to be used for this sort of thing -- but they rely on fairly heady and technical processes, if you're not comfortable with the command line I don't recommend them.