Pictures from my iphone 4 rotated or flipped after copied to my hard drive?? (Windows 7, iphone: newest iOs)

Okay, i take a lot of picutres with my iphone and i like to have them in chronological order.. But here's my problem. Okay, so i plug in my iphone to my laptop, sync it, and click "open folder to view files" and then i copy all my pictures to my computer, you know, so i can view them with all my other pictures from other cameras and everything from the past.

Okay, my pictures are all upright, not rotated 90 degrees or flipped horizontally.. But when i hook it up to my computer and after i click "open folder to view files", i look and see that the majority of them are rotated.. I know i could flip them easily on my computer. But my problem is that when i do that, it changes the "date modified", which is what i go by so i can chronologically flip through all my pictures since the beginning of time.. But after i flip it, it automatically changes the date modified to that time (January 27th 2013). That's bad! Now i cant put them in with all my other pictures that are actually correctly organized.. Is there any way i can make this stop happening?

I have an HP Pavilion laptop with Windows 7, and the newest iOs (6) on my iPhone 4.. I dont think its a problem with my laptop either, because i actually tried it on another Windows laptop and i had the same problem... I dont even think its a problem with my iphone (like i said, the pictures arent rotated on it, they are just like normal..) But on my laptop they are.. Is there anything i can do to fix it? I think as of now my only solution is just getting a program that lets me manually change the date modified to be the same as originally before i rotated it, but i dont want to have to do that painstaking task every time in my life i put pictures on my laptop from my iphone! Has anyone else had this problem, maybe its a bug? Or even if there was a way to flip them without them changing the date modified, i could settle with that.. Any suggestions?