I have a few pictures that are not as wide as the majority of pictures in my project. Is there a way to eliminate the black edges on these "short" pictures without distorting the image.
Use Pan/Crop to "zoom" in on them as much as you need to. You'll end up cropping some of the top/bottom, but you can get the width to fill the frame that way.
Here is an amatuer's graphic artists approach. Yes, follow Chienworks' advice - but then add a really classy effect.
Overall, place the "correct" ratio sized still over a slightly "lightened" fill frame cropped version of the original still. The appearance is a "framed" version of the still you want. Have the original still fill say 1/2 to 2/3 of the frame. I've seen this done in magazine publications and news reports etc etc. It looks very special and classy. You could even "feather-edge" the orignal - yes?
The result will be a still floating [ not moving! ] over a much larger version! Kool!
Shredder outlined a decent approach in this thread some months ago. It's nothing to do with stretching - you can do that as Grazie suggests or not. Either way you'll get a result.
But if you have several images after one another it's probably best to have a steady format so it doesn't jump too much.
Here's my two cents. All the methods suggested work, and have a place, but are more suitable for slideshow type presentations. When trying to fit a image to fill a video frame, and you only have a single still image or just a few scattered through the video, you want them to blend in as if they are the video itself. To do that the key is to have the still image ratio set correctly, then it won't have the 'black borders' either on the sides or at the top and bottom.
I think Kelly wrote a piece awhile back, was going to point to it, but can't find it. Maybe someone else can remember which thread I was thinking of.