It looks nice..I think you just need to bring the sideboard little to the left(place it in the centre) add one more line of photos to fill that space up to the top of the sideboard..then place two small lamps on two ends and vase in the middle..collection of frames will create an art work.. Don't take them down it will make you smile every time you look at it, it's a reminder of good times and memories :)

Maybe bring Side board to the left a little then paint it brown or wood black

I think you have should look at the picture wall as a single large rectangle. You have two options. You could make the bottom, top and sides of the rectangle all straight lines, so the top edges of the pictures on the top row would be in line, the bottom edges of those on the bottom in line, the right hand sides of the pictures on the right should line up, and so on. You could be more random with the "filler" pictures. Or you could make the centers of each picture line up, so the centers of all the pictures on the top row are on the same imaginary horizontal line, same for the bottom, and the centers of the pictures on the left and right hand sides line up vertically. Then fill in the rest of the rectangle using the same principle. I think either choice would give less of a crowded and slightly off balance feel than the present look.

My two cents. I prefer (as suggested above) that the sides of the 'rectangle' of photos be lined up. Also definitely agree that the sideboard should be in a dark colour to balance and anchor the wall.

I agree with all above in that either the sides or top & bottom need to be squared off