Alignment of different-sized objects in Row

Use BaselinePosition

framed1 := Framed["", ImageSize -> {100, 100}, BaselinePosition -> Top]
framed2 := Framed["", ImageSize -> {250, 75}, BaselinePosition -> Top]
framed3 := Framed["", ImageSize -> {50, 50}, BaselinePosition -> Top]

Row[{framed1, framed2, framed3}, "   "]

It may help to review the other Framed options.

One may also find Grid useful:

framed1 := Framed["", ImageSize -> {100, 100}]
framed2 := Framed["", ImageSize -> {250, 75}]
framed3 := Framed["", ImageSize -> {50, 50}]

Grid[{{framed1, framed2, framed3}}, Alignment -> Top]

If a special separator is needed it can be Riffle'd in:

Grid[{{framed1, framed2, framed3} ~Riffle~ "⊙"}, Alignment -> Top]