How to transfer photos from my computer to my iphone?

Every time i drag the picture to my iphone profile a message pops up that says "can't copy item'' not sure why but i reprogramed my phone & turned off my phone and computer several time please help.

If using you're using Windows, or if you're using a Mac but you prefer not to use iPhoto, you can sync iTunes with a folder on your computer. If you want multiple albums on your iPad, I recommend placing the individual folders into a larger folder. In this folder, you can have more subfolders than you desire to sync with your iPhone and iPad because you can individually select which subfolders you want in iTunes. Organize your photos in iPhoto or foldersPlug in your iPad and open iTunesClick the Photos tabCheck the box to "Sync Photos From"Select "Choose folder… " from the drop down menuBrowse to the desired folderSelect which options you preferClick syncDepending on how many photos you're syncing, both methods have the potential to take some time.