Ronique Gibson Yes you can mix and match picture frame colors. The trick is to also incorporate the colors of the composition into consideration as well.
With black and white photos the ability to mix and match colored frames may be easier, while with colored photos you don't want to over power the space or the picture.
My advice is to look at the colors in your room, not just the wall and judge if you want them to all match or not.
Here are a few ideabooks that will show you examples of mixing and matching picture frames. The first one has a grey wall example.
laurahahe Lay your frames out on the floor first to see if they look good before hanging them. You can also spray paint your frames, white looks good, but depending on your color scheme you could bring in a different color as well, charcoal or raspberry come to mind
Work up the walls.
They're prime real estate for your collection. Not only do they keep your objets on view, they free up tabletops for productive use.
think outside the frame. You can intersperse objects and other media into a gallery wall. You can also use frames in non-traditional ways! Try having the photos printed on metal, on different types of paper, and on wood.
different shapes and sizes of frames, some not in the frames and not same shape as frames, other things on the wall...a wand? A letter. All same color theme make it not overwhelming.