Excel formula

1.      =IF((C10="")*(D10=""),"",IF(C10>D10,$B$10,$E$10)) this formula correctly fills G16 with either B10 or E10 data.

2.     G17 contains a graphic which is linked to a named range and which works fine

         =INDEX('Linked Picture'!$AA$31:$AA$46, MATCH('Linked Picture'!$G$16,'Linked Picture'!$Z$31:$Z$46,0)) this formula correctly picks a graphic depending on the value of G16

When I select the graphic in G17 the code is =FlagLookup9

I have tried =IF(G16="",""),FlagLookup9 - I want the code to check if G16 is empty and if it is do nothing otherwise select the graphic referred to in FlagLookup9.

When I try this I get a message "This formula is missing a named reference or a defined name."

Any pointers where I cam going wrong? Thanks.