Tried a resize. OK,on edit I guess it didn't work. However, on properties it says they are something like 800x500 on the full sized pictures. I'm confused. Maybe taking out two pictures will speed up downloads.
My only concern will be lateral twist on the hitch. I would weld a plate over your angle irons and put a gusset on each side of the hitch down to the plate for added support. Other wise it looks like it would work for ton of lifting situations