If you have icloud installed on your pc go to C:\Users\username\Pictures\Photo Stream\Uploads (win 7 location) and just copy your pictures into that folder.
They will appear on your devices under photostream in the photo's app.
Windows XP: \Documents and Settings\username\Application Data\Apple Computer\iTunes\iPhone Software Updates
Windows Vista & Windows 7: \Users\username\AppData\Roaming\Apple Computer\iTunes\iPhone Software Updates
If you have downloaded the file from a direct link then copy the ipsw file into...
Keep getting error 3200 and 3002 no matter how many times I try...
This is BS
[edit]
Fixed, copied it into the folder itunes downloads updates to, and it did it first time.