Yeah. Avoid iTunes for this at all costs. It is just horrible with syncing photos.
I recommend you make a Dropbox account. It is free, and gives you 2GB of free space.
Download the Dropbox folder to your PC. Once downloaded drop your photos in the Dropbox folder.
Now on your phone, download the Dropbox app from the app store. Open the app, sign in, and your photos will be there. Simply snap a screenshot to save the pics to your camera roll or tap the box with the arrow and tap save image. I personally think its is better to snap a screenshot. Just faster, and does the same thing.
You can do this same exact thing with SugarSync. Available for your PC and iPhone. SugarSync gives you more space too.
I recommend you load the pictures while connected to wifi. If you load them in the Dropbox/SugarSync app while using 3G data the picture quality will reduce.