I can't really get a sense of your diamond from this photo. Do you have an ASET or an Idealscope? It's impossible to work out your stone's light performance from a photo like this. Did the vendor give you any other info? And can you give us a little more info on the setting?
I'm concerned the top left prong is not seated correctly at the corner. From this pic, it looks like there may be a gap between the right angle of the prong and the stone. Take a closer look.
I double checked with the spacing on the top left prong, it does look it has a space in the picture but i think it is just a shadow, will post more angles later for you, thanks!
It probably depends if you are swapping it for a decent cut or not, better cuts give better edge to edge light return so they appear bigger.
Most people cannot tell the difference between and F and a G. Depending upon how much you go up in size, (if it is enough mms) that is something you can visibly see.