Can't see/edit texture files?

Hi Guys, it's me again with yet another question for you. How come with some aircraft, no matter that graphics program you use you just can't the texture files to open? I mean, they're just .BMPs and I can't even get them open in Photoshop 7. How can you get these files open to edit them a bit?
Now, you all know I'm a newbie. I wouldn't reskin someone's plane and pass it off as my own. However, since I only fly a few different planes, I DO like to slap on my own nose art or something just to personalize it.
Until next time, Take Care.
Sue
Now, you all know I'm a newbie. I wouldn't reskin someone's plane and pass it off as my own. However, since I only fly a few different planes, I DO like to slap on my own nose art or something just to personalize it.
Until next time, Take Care.
Sue