You are VERY strongly recommended to not spend time designing placement-specific ads, because I can virtually promise you you'll get better CTR from Google's responsive ad formats. And I've observed that test being run several times consistently, including vs very impressively designed whizz bang animated placements. Furthermore if you are doing product based remarketing - it's a HUGE step up in technical requirements to add a product feed to image ads you've designed yourself (although this IS something worth looking at - Google Web Designer app will let you do this, but again VERY technical and not necessary).