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Email the pictures to yourself. Pick up the email on your iPhone. Then click the left facing arrow at the bottom of the screen and select Save 'number' Images. The images will appear in the camera roll.
 
Emailing and saving works, but this way is easier.

With a jailbroken iPhone with iFile on it, browse to the folder containing the photos (any folder). Tap on the blue arrow to the right of the screen for the photo or video wanting to be on the camera roll. This will show you the file properties. Scroll to the bottom of the file properties and tap on Add to Camera Roll. Voila!!

Likewise, if you tap on a photo from iFile as if to view it, there will be an icon at the bottom of the screen that looks like a folder with an arrow on it. Tapping that icon will add the photo to the camera roll.
 
Another question - Is it possible to stop my phone from saving email images or images off the net into my camera roll? If I'm downloading wallpapers etc, I don't want them in my camera roll.
 
Saving an emailed picture to your camera roll

1) email the picture to yourself
2) open the email from your iPhone
3) click and hold on the picture
4) select "Save Image"

The picture will now appear in your camera roll
 
1) email the picture to yourself
2) open the email from your iPhone
3) click and hold on the picture
4) select "Save Image"

The picture will now appear in your camera roll

Did you read the OP? The OP wanted to copy FROM the PC to the iPhone. Nothing about using the internet.
 
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