How to fix focal length properties for a picture taken from an iPhone?

I took several pictures on my iPhone and then put them on my computer. I went to edit these photos in Windows Live Photo Gallery which I have used before. When I tried to edit some, I had no problem. But others would give me an error notice that said "photo can't be saved due to its properties".In the properties window under the details tab the 35mm focal length section was highlighted, so I'm guessing this was the problem area. But no matter what I put in there (it only asked for numbers and I have no idea what is right) it would say it was wrong. Also in the pictures that I edited successfully, the 35mm focal length section was highlighted and empty.

Recommend you mention which version iPhone you're using.

If it's 4 and the photos with the problem are rotated, you're not alone. This has been a problem for several years. Rotate them first. Then try to edit.