Many email marketing companies use the same image, or one very similar, on the landing page as on the marketing email, yet normally opt for different copy for the change in function. This shows one of two truths: either the original image or the one on the landing page is not optimal. They have different functions.
Almost by definition, an image used in a marketing email will be shallow as it has to catch but not hold the readers’ attention, and all in a fraction of a second. If it’s too pretty, it is obviously too distracting. The same goes if it is interesting as it will deflect the reader from what you want them to do; click through to a landing page. 
Therefore, shallow is good.
By clicking through to the landing page the subscriber is letting you know that they are interested in whatever product you are pushing and it is now up to you to convince them that it will solve a particular problem, need or indulgence. What they see next can make or break the deal. Reusing the image from the marketing email is not going to reinforce or encourage the reader.
The image on a landing page is there to convince someone, who has already shown they are half way to buying, that they should part with money. What we need to do is ensure that the subscriber is reassured that their decision to click through was a good one. There’s nothing like massaging the conceit of a customer to get them to complete. The image on the landing page should explain the unique selling point, something that was impossible to do thoroughly with the one in the marketing email. It’s expansion, not repetition, of the point that’s needed.
You should not ignore the original image when coming to a decision on what picture to pick for the landing page. You’ve got a base, flimsy at this stage, to build on. If you’re selling a luxury holiday and captured their attention in the marketing email by an image of a beautiful sandy beach, blue sky and sea, then one of the hotel room, perhaps with the balcony view in the background of the same beach, will work with the original image. They can dwell on it for a while: but not too long.
The image of the landing page is often most effective when it works on the emotion of the reader. That’s why images of babies and grumpy cats are popular. If, instead of luxury, you are selling an activity holiday, consider something along the lines of someone reaching the top of a mountain, breasting a hill or, my favourite, sitting outside a pub after a hard morning’s walk, with drink in hand.
Thankfully, holidays are not all about challenges. You have to work out what will attract those on your split email marketing list, what motivates them, and obviously what excites them. The landing page should make them feel excited, or happy, or envious.
