I hope someone can help me out, I have 4 glass pictures to put on a wall, my wife wants there to be the same gap between the top & bottom pictures & them side by side, I have included a couple of photos to show what I am trying to get across.
I'd suggest you pick up a level as it will assist you in making short work of this project. It will allow you to ensure the frames are square and level with the floor, and you can also use it to establish equal spacing.
Start at the top left-hand corner and mount the first frame. Measure from the fixing point in the middle of the frame to the outside edge of the frame. Times that by two and add the width of the level. That is the distance from your first mounting point to the second for the right-hand frame. To find the location of your bottom mounting points, measure from the fixing point on a frame to the lower edge. Then, measure from the fixing point to the top edge. Add these measurements together and the width of your level. That is the distance from your top mounting points to the lower ones. I've added a rendering below to illustrate.
Use the level to make sure all the mounting points are in line with each other and level and square to the floor.
If you are happy to have just a constant spacing and are not particular about it, you can space four mounting points equally on the wall if the frames are square. Make sure the distance between them is large enough to accommodate the frames in-between. By making the spacing between the mounting point equal, you're also ensuring the gap between the frames is equal.