This is by far the yellowest photo I have, you may want to put on sunglasses.
It is a brimstone (Gonepteryx rhamni) on a dandelion:
Olympus XZ-1, 112mm, ISO100, f8, 1/400s
Nothing subtle about it! Photographically, it is nicer to set these butterflies off against their complementary colours, like this:
Male brimstone:
Olympus XZ-1, 112mm, ISO100, f8, 1/100s
Female brimstone:
Olympus XZ-1, 112mm, ISO100, f5.6, 1/400s
But it is Yellow Wednesday, so the yellowest one has it!